You need more troop choices to hold objectives. At 1500 points you need at least three scoring units preferably four.
I tried a SG army, but found they were just too expensive and too squishy. Sounds strange given they have the best armour save, but with no invlun and with loads of people taking plasma a 5 man squad just doesn't last. There is no "wound soak" in the squad, you are paying for power weapons on all of the models and then losing it when one dies without if having done anything.
BA Vindicators are great, but a multi-melta D squad? What do they do? They need to be within 12 inches to be effective?
If you want to run with the 2 SG squads then something else must give.
Firstly I would drop the D squad. How does the libby dreadnought do? With only one unit doing a drop pod assault I would have thought it gets toasted after it arrives as everything will concentrate on it. You could save a few points by just having a regular Furioso. I would also possible drop the other Vindicator, but it depends on points.
I would then get a scout squad with sniper rifles and cammo cloaks. These guys can go to ground on an objective for a 2+ cover save, or just snipe away. These are your cheapest objective holders and are pretty much a must have. Don't under estimate the sniper rifles - yes the weapons generally do nothing (but the scouts hold the objective), but your opponent fears them just in case they start picking off special weapons. In a tournament I had four games of them killing nothing, then in the fifth game they sniped out: a multi melta marine, a meltagun marine, the Terminator with the assault cannon, the terminator with the cyclone missile launcher.
You've got nothing anti air, BA don't have a lot of choice at the moment it's pretty much Stormraven or ADL with QG. The stormraven could then deliver the dreadnought into combat, but its a risk he'll arrive too late to do much if you roll badly for the Stormraven. But it's your choice - if you want to play ignore the flyer then it is a valid tactic and the BA jump pack does have the manouvrability to try to pull it off. You will get toasted by flying MCs from the Nid codex though.
I've never really tried bikes with BA, but an Assault squad gives you the same movement and they are troops for holding objectives (although they don't have the extra toughness or cover save).
Your choice, but getting a scout squad is a must and I would try to squeeze in another troop choice as well.
