First impressions is everything Windu. You didn't do a good one. If you wonder why people will try to counter you at every corner, search no further.
Nevertheless, there's only two civs so 30 space and 30 ground units doesn't seem that excessive. Granted, it is a lot compared to any other RTS but it would be nice to have a huge variety of units instead of civs.
Though I do not like the Tie Crawler myself, I cannot see your reasoning behind:"There's no need for it".
First off, it's supposed to be a cheap attack tank. Do the Empire have anything in the movies that ressembles a cheap attack tank? No.
Thus they decided to go with the Tie Crawler. It may be ugly, I may dislike it but we'll see what it really does ingame before judging it.
BTW, if you wanted pure movies, you'd have near zero diversity.
Let's round up the pure canon units:
-Tie Fighter Pilot
-Imperial Class Star Destroyer
-Super Star Destroyer
-Death Star I & II
-Lambda Class Shuttle
-Rebel Trooper(Hoth/Endor/Tantive IV)
-Calamari Cruiser(mc80& mc40)
That's a LOT of units...seriously, they add EU units for the sake of diversity.