The TAR is a pretty handy gun. I really believe the biggest reason for the ergonomic changes in the X-95 were to better suit the large portion of their forces trained on the M-16/M-4 platforms.
I really don't think so. Having extensive experience with both, the X95 has a plethora of very minor changes to fix small problems with the TAR21.
The gap between the pistol grip and the magazine well is much smaller on the X95. While I personally don't think "accidentally dropping a mag by bumping the release" was ever a problem with the TAR21, it WOULD have been a problem with the X95. You can see on the polymer shell that they intended for the original release to be there, but they had to relocate it out of necessity. I think it's a good tradeoff for the shorter length of pull - with a flat buttplate, the X95 has a LOP a little shorter than an M16A1.
The side charging handle, similarly, is not as intuitive as the forward one, but fixes some issues. As has been noted, it makes it easy to mount accessories. Another reason is the very long cocking handle bar on the old TAR21 was at an odd angle, and would also flex with use, and scrape against the gas block. This would make it VERY stiff to charge. The X95's charging handle bar is not only short and rigid, but in-line with the travel of the bolt carrier. Having the channel closed off by the railed handguard also makes it infinitely easier to remove the handle and cocking bar on disassembly.
Even the cutlass handguard on the X95 has been made flat on the bottom, and more vertical in front. This lets you keep the "6 points of contact" method, but makes it much easier to shoot prone or off a rest, something that could be very awkward to do with the old TAR.
The X95 is a bigger upgrade than it looks, I made the switch and never looked back. I have seen no accuracy difference between them.