Great question, I think has been rarely asked here before;
I'm far from ultra-competitive,
but here's a few I enjoy for missiles or emplacement 'choke points':
RotS starter map.
Clone Strike map (muunilist)
DeathStar/Landing Bay (easily)
Christophsis bridge,
Rhen Var,
Kamino interior
Koriban,
Coruscant Transit*
Bespin interior.
Pirate base.
Theed (hangar side)
Endor to a lesser extent.
those are great stuff for autodamage choke points.
theres a lot of spaces that narrow to 2 squares wide by 4 squares long and are bounded by pits or walls.
there are a couple of downsides though;
doors,
damaging your own units (especially on the Death Star map hehehe)
Maps you'd want to avoid so much,
Hoth,
Geonosis,
Bespin (landing platforms)
Endor somewhat
Naboo Plains/Theed
TCW Palace,
Jabbas palace.
Predominantly, because these are so open,
there is no significant terrain asymmetry advantage or as many choke points
