I happen to understand how the OP feels ..I went from SONAR 6 PE to X 3 PE ...
When I made that move or more correctly put " that gigantic of a jump in a SONAR upgrade " .....
I was like Whhhaaattt
I kept using 6 PE for a long while I sure enjoyed all the extra doodads ..Addictive Drums , Rapture , B T ect...
As far as my 2 centavos goes , I would keep X 3 installed

How else would you be able to deal with the learning curve if and when you decide to tackle it ?
In my case I chipped away at the L C over a period of a couple of years ....
In addition to that , over time I found that there are a lot of excellent plugs, tools and features that were pretty much locked into X3 that couldn't be used in a former version of SONAR...
The Pro Chanel , the Blue Tubes Plugs , ARA / Melodyne integration where you slide a monophonic audio track over to a midi track where ARA will then convert the audio over to midi so you can use a VST synth to play the part..
3 Pro Chanel console emulations + all the integrated additional functions of having the ability to custom create your own Pro Chanel signal chains using the plugs that are available as Pro Chanel only plugs in the first place

I can go on and on with this but I won't ...I'm not over here selling hoover vacuum cleaners door to door
In my case "in retrospect " , what helped me the most was I started hitting brick walls in what I was able to do in a Pre SONAR X 3 environment ...I had some very good 3rd party stuff , but I found a lot of things seemed disjointed with getting it all to work in a simple easy way ...
Eventually over a long period of time I started doing A B comparisons of my music by bringing over mix's and stems , or even single tracks I had done in SONAR 6 over to X 3 ...
I found that worked pretty good as a way of cresting the learning curve

IMHO, between the heaver duty mastering grade quality plugs and added functionality that X 3 brought to the table I found that over time it was worth my time to bite the bullet and crest the learning curve ...
good luck OP ,
Kenny