Not having to care where you hit a tank has been one of the vehicle battle staples of the original Renegade since the beginning. Having to stop and take care where you hit a tank for most effect is less arcade, and more realism. Directional armor, I might be able to get used to it, but the spirit of driving Renegade style vehicles would be "hurt" in my eyes, especially if they go with detailed weak points. With Renegade the small bonus the flanker got was the nearly free kills on the "repairing supporters" (Hotty/Tech), take out the repairs and the campsite dissipates if your team pushes the advantage. Plus, blocking the enemy tanks retreat so they're stuck in the open to prevent them running to repair would become a less of a good idea than in the original.
If you want your tank taken down in a few hits, I can think of several games where the tanks don't last long at all versus infantry, and an RPG up your tailpipe destroying an Abrahams is all too common with inf versus tanks. <(Just an example, don't mistake it as something else) I abuse tanks with Engineer type classes in those games, so I never drive them because of it. Original Renegade, it can be bad enough with Ravs vs a Med. tank or similar, if the Rav/PIC knows what they're doing. Just wanted to get my words in on this.