There’s a split opinion on this topic, and you can find lots and lots of discussion around it, specially on Steam. I personally agree this game should have gates on walls. Otherwise, we are still going to be forced to wall-off sections, build towers, etc., in order to increase our defenses.
I recommend NOT using 1x, but 1.5x game speed. 2x is just too fast/unrealistic for me. As for proyectile speed, I think arrows are fine. Maybe missiles should get a boost?
This is probably the most polemic request on your list, but you do have a point.
Letting archers, villagers, and maybe even slingers garrison inside towers seems reasonable.
Allowing non-military units, such as priests and villagers, to garrison inside town centers sounds interesting to me, since those units don’t have a chance most of the time. I would even go a little bit further: letting artifacts garrison inside town centers, so it is mandatory to destroy the TCs in order to gain control over them.