Spikes could be a problem for your team with five pokemon being hurted by them. Skarmory can easly come into Metagross, Swampert, Blissey and Aero, as without cb you will not do much to it. Bulky Waters can give you a problem (especially Swampert) as they will come easly in your three main attackers and Bliss can only sponge them for a time (cursepert will beat it). Suicune with Spikes is a real problem.
I recommend to put EQ instead of SB in metagross and give Aero (or even Meta) choiceband. Without it you wont do much to fhysical walls like cune, swamp or skarm. Dont think you can beat Suicune with Boah! The other real problem (which is the same abaut the ph.walls is your big hole against water attacks.
You can try another sweeper instead of one of your three. You cant try CB or SleepTalk Heracross. In can really benefit from BulkiWater switches. With some HP Evs (like 196 I think, you will want 222 Spe for Tyrano), in can take few surfs. It is another reason you will want to use a Rapid Spiner... or Maggy! Other things like Zapdos are useful options for yout team, or any other spc sweepert. A Wisher can be another useful option to support Boah, and Metagross. You can use Celebi, who may help agains Waters. If you want wish you can try sala, who works well with metagross, and maybe with Tyranitar too.
Edit!: Like Gotei said give Metagross some speed, SpD is not really needed
and Crunch can be more useful than IB. Whirlwind is recommendable. AND GIVE SWAMPY DEFENSE, NO SPD, i didnt realise it. SpD does not go well with swampert, as other waters will generally beat you and hp grasses as well. Defense is needed to switch into tyranitar,aero and others, that skarm cannot handle. In your swamp rest goes well with aromatherapy, protect with toxic and SS. You can decide XD. And CBLax is another funny option to consider, it comes easly in waters and electrics (use something like adamant 252Spdef, 252 atk 4hp, as you wont take phisical hist with it. However it normally goes bad with bliss.
I usually battle rse in netbattle, so if you want to battle with me... Maybe you should use another team. I know this XD