The SP Basics would get no play without the SP Support. Tank Dialga without PokeTurn? Useless. Infernape's Fire Spin without Energy Gain? Too slow. SP decks without Cyrus? Not consistent enough.
I don't think Power Spray was needed, but without the other support people would be moaning about how SP was a failed concept. Try building an SP deck without any TGIs and Cyrus . . . it's rubbish.
Well, that's fine by me. As I said before, this format was perfectly fine before SP Pokemon. They should not have gone tampering with the format with such radical concepts in my opinion. The basic problem with the SP concept in general is that you must have one of two things for it to work within the game: since they are restricted to being basics, they must be strong attackers and function like they are Stage 1 or 2 Pokemon, or they would be too weak offensively. The problem here is that this makes them too over-powered because they are after all Basics, and are very fast. You can make them fast, but you can't make them too strong or they are unbalanced. The second option for making the mechanic work at all is the following: make the Pokemon so that they are not too strong offensively, but give them strong Trainer support so that they can have different means of defeating opponents rather than just by a head on attack, which clearly wouldn't work against Stage 2 Pokemon which have too much HP and attacks that are too strong for that to be a fair fight. Clearly, it seems PCL took the latter route with Platinum, because that is exactly what we saw. The strongest attack any SP Pokemon in Platinum could do was Weavile G's Team Attack, which could do up to 70, given you had a full bench of SP Pokemon. There was also Dialga G, which could use Second Strike for 70 if the Defending Pokemon already had 2 damage counters on it. I am ignoring the Lv.X SP Pokemon for now, but the Dialga G Lv.X and Palkia G Lv.X could both do 80 for four Energies. For the most part, the attacks themselves weren't very impressive compared to what we had recently seen before. The Trainers that the SP Pokemon is what made them playable. The problem I intend to point out in all of this is that in Rising Rivals, the Pokemon suddenly gained a lot of offensive power and even more Trainer support. This tipped them over the edge and made them too over-powered from my observation, because the Trainers in Platinum were still very good for them, but in Rising Rivals they are Stage 2 Pokemon that skipped evolution and had a pool of powerful and easily abusive Trainers they could exploit exclusively. Considering they were already working very well in Platinum with the their speed and already eliminating set up decks from the metagame it is clear they didn't need any more help to make them dominant, but they got it.
And what Scizor says about Kingdra, Machamp, Gengar, and Poketurn is correct. Specifically about the first three, they are so able to exploit BTS like no other Pokemon can that makes people want BTS limited, which would be a silly thing to do. For any other Pokemon that evolves, BTS is no big deal, and there are often times less inconsistent ways of putting your evolutions into play. But those three are a particular three that are very capable of exploiting it, but that is not grounds for limiting the card.