Bass and drums are super important. Together, they set the underlying groove and feel of the song more so than any other instrument does. If they are not right, and properly working together as a cohesive unit, no matter what you do with the remainder of the instruments, you will be struggling to get the song to sound right.
The "groove" I refer to is the way the part feels and moves in the song. When the drummer and the bass player get in the "groove" and are working together, the song really could be finished off with just a vocalist. The right groove "makes" the song. The wrong one or lack thereof, on the other hand leaves the sing feeling "not quite right".
A good example is a song I'm currently working on with another writer. I think we have replaced the drum track several times and the bass has been replaced around 5 or 6 times..... I think the other writer just recorded a 6th bass track. All in an attempt to find a workable groove for this song.
Same thing here. I don't have a bass guitar and I don't play drums or have a kit. So I too have to rely on midi and synths. With a drum synth package, you can get some pretty nice licks and fills to compliment the song. With a proper midi sample of a bass, and some minor keyboard skills, a bass part is fairly easy to play.
Just me.... but I tend to sing close in to the mic. With a pop filter, and singing 45 degrees off axis, (past the mic) and having the levels set properly, I sing pretty much like I did on stage in the day..."eating the mic" and back off only a few inches for the power stuff. I think the "distance" sound is more related to the reverb being used and how much is in the signal path as opposed the the distance to the mic. Unless you are standing back 4 feet, that should not be the issue. It sounds like a strong level of small room reverb. Because, the distance is only on the vocals. The instruments don't have that sound.
Here's what I do. Not saying you should follow suit..... just food for thought. Vocals: I run the track dry. No FX at all. I set up a vocal bus. In it, I install a Cakewalk studioverb2 plug. I select the default dark plate. I only adjust the percentage to 15%. Done. In the master bus, I will have Ozone4 with a custom preset for overall shine and polish, and again, I may drop another Cake Studioverb2 dark plate at 10% to gently blend all the instruments. At that level, the reverbs are very low and nothing really stands out. It's simply a gentle touch of verb. Depending on the song and the feel I'm going for, sometimes there is no reverb in the master. However, the vocals almost always get 15% in the vox bus. Sometimes more than 15% sometimes less.
My 2 cents