I'm on X3e, and rather than pore through all the latest features in the newer versions, I'm only really interested in a couple things, and am wondering if these are improved, as they are the only reasons I would upgrade. It seems like Sonar upgrades are usually just about adding more and more features I won't use. Here are the couple things I'm wondering if they're improved:
 
1) Better handling of vertical space. Is it any easier to manage track heights and those horrid take/automation lanes? I spend way too much time collapsing and expanding blasted lanes to free up vertical space. This could be so much easier. Is this improved since X3e?
2) Is it any easier to insert or remove measures in a project? I'm frequently deciding to add or remove bars from my projects, and I have to make sure I have everything selected just so and have selected all the check boxes in the insert dialog (BTW Insert Time/Measures - NOT in Insert menu --- WTF???). If I do anything wrong, my piece may be hosed, and sometimes I don't notice until way later when it's too late.... It feels like I'm cutting diamonds. One false move and....  All I want is a simple "This part needs to go on a few more bars" or "I don't need this section at all". Sonar sometimes feels aggressively un-musical in that simply inserting or removing measures is so damn hard. Is that made any easier in future versions?

I'm not competent to answer your specific questions, but having moved from X3 to platinum, I love the concept.  In effect, the entire community are beta testers and idea generators for Cakewalk, and we're the customer, so they're listening.  It's the best way to improve the product I've seen. 
 
Also, I like the command center and the seamless integration of new software. It's made it very easy for the upgrades and fixes.
 
You could spend $150 and get some kind of sonar X4 on Jan 15, 2015 or you could do what they did, and spend that same $150 and get the monthly fixes, adjustments, and add-ons, while monitoring the forum conversations. For me, it was a good deal.

No. Those two areas have not changed. Sonar 2015 is essentially X3 with more (extremely useful) features. There have been feature requests regarding the specific issues you are talking about so get thee down to the Feature Request sub forum and do some voting.
 
I'm happy with the way things are going but of course things can always be improved.

I would be extremely disappointed if any of my own inserting & deleting of time/measures went wrong.
 
It really is quite simple

I'm thinking OP wants the block "arranger" type features certain other DAWs apparently have. Can't say I wouldn't like something like that myself. I get by though.

Beepster
I'm thinking OP wants the block "arranger" type features certain other DAWs apparently have. Can't say I wouldn't like something like that myself. I get by though.

The term for that, in the video editing world at least, is "ripple editing". Something like that would be useful and in most video editors that have it, you can turn it on or off so your editing behaviour operates as desired for a given situation.

jkoseattle
 
2) Is it any easier to insert or remove measures in a project? I'm frequently deciding to add or remove bars from my projects, and I have to make sure I have everything selected just so and have selected all the check boxes in the insert dialog (BTW Insert Time/Measures - NOT in Insert menu --- WTF???).

LOL - Jim, I've moaned on and off about this particular idiosyncrasy since the menus were changed in X1.
 
As I use SONAR quite a lot to compose and arrange, I'm always using the Insert Time/Measures and the Cut/Delete Hole features.
 
What I do like in Platinum, and what I've used to great effect to restore some of that 'familiar' functionality is the Custom Control Bar Module.
 
I've assigned the nine available buttons (more would be nice) to features and functions I either use a lot, or to those I like to operate with a single mouse click, as opposed to the many two-step clicks X1 (unfathomably) introduced.
 
Hence my full list of nine Custom Module buttons, including Insert Time:

1. Undo
2. Redo
3. Browser - toggle open/close
4. Preferences (yet another baffling decision to hide this under Edit>Preferences instead of the tried and tested 'Options' button )
5. Bounce ('Export Audio')
6. Fit Project (to screen) - I've also assigned this function to the single-stroke keyboard shortcut 'F'
7. Centre View (puts the Now Time Marker in the centre of the Track View)
8. Insert Marker
9. Insert Time/Measures

 
To make life even easier (as per using the 'F' key above), I have also assigned a fair amount of keyboard shortcuts to various tasks, and for the most commonly used functions, I've tried to create single (and logical) keystroke shortcuts:
 

 

jkoseattle
1) Better handling of vertical space. Is it any easier to manage track heights and those horrid take/automation lanes?

 
I tend to collapse the bus pane and the dock and just scroll to see what I need. I'm not sure what could be done here to improve matters - I could make the tracks less high, but then I can't see what's in them. A bigger monitor seems the only solution to me.
 

2) Is it any easier to insert or remove measures in a project? I'm frequently deciding to add or remove bars from my projects, and I have to make sure I have everything selected just so and have selected all the check boxes in the insert dialog (BTW Insert Time/Measures - NOT in Insert menu --- WTF???). If I do anything wrong, my piece may be hosed, and sometimes I don't notice until way later when it's too late.... It feels like I'm cutting diamonds. One false move and....  All I want is a simple "This part needs to go on a few more bars" or "I don't need this section at all". Sonar sometimes feels aggressively un-musical in that simply inserting or removing measures is so damn hard. Is that made any easier in future versions?

No, this is still pretty crude. In fact I think it's got worse, because it's harder to select sections of music because dragging the lasso across track folders tends to pull in any clips that overlap with the ones you wanted to select. So you end up having to Ctrl-Click on each one individually. And then hope you didn't miss a clip down on track 32 or whatever. And when you drag them, hope they snap to the right bit (which often won't happen if one clip starts slightly before all the others, for example). And hope you don't hit one of the rendering bugs which shows the clip in a different place to where it'll end up when you stop dragging it. Then manually fix all your fades - either add new ones if auto-crossfade is off, or remove any now-excess fades if auto-crossfade was on. Alternatively try the copy/paste method - and hope that it puts everything in the same tracks you cut them from (which it won't, if a different track is selected to the first track that contained the data you cut from). That will leave any markers behind, of course - for that you need Cut Special. Also, see above caveat about moving data when one clip starts slightly earlier than the others. Usually you end up opening the inspector to note how many ticks out they ended up, re-select all these clips, and then Slide them to where you really wanted them to go.
 
(Why, yes, I do spend a lot of time wrestling with this. Why do you ask? :) )
 
Also, sometimes the 'Insert Time/Measures' doesn't do anything at all now. Repeating it usually works. But even when it does work, the graphics in the Navigator window are messed up.
 
But no, I'm not aware of any sort of ripple edit feature or other simple way of moving sections flawlessly, and yes, arranging in Sonar is really inconvenient, still. My suggestion is to slip-edit everything to measure boundaries, don't use track folders, and group the clips in whole sections when you're happy with them. That way you can select and drag things with a single click and there are far fewer things that can go wrong.