Too many tactical marines.. if you have to have 10 man rhino and a
CC upgrade take a fist. (although I hate them and prefer missile melta combi melta.PLasma cannon flamer combi flamer.)
Still lacking (serious) anti tank that can safely take out landraiders.. (one stunnable dreadnought and one bike squad does not make a dual raider list quake
)
Having lost the pressure and just having an "if I go first.. pawn sacrifice "isn't a whole theme worthy of staying with UMs . Consider taking blood angels or wolfs with vaguely the same layout..for the cheaper devs (take 2 squads of long fangs and then don't take missiles in the grey hunters..etc) and the more flexible troop outlays once you've take a few of those cheap support fire units.
Away from codexs at mo so can't sketch them out at the mo.