Except...Decade wasn't ruthless. He ACTED cold and aloof, but in crunch time, he pretty much always revealed a heart of gold, so to speak.

Yeah, to protect someone he would have a heart of gold. But who is he protecting in this fight?

Tsukasa isn't a killer, regardless of what that stupid movie tried to say otherwise.
Hell, that's the entire reason why the Rider War started! Tsukasa's refusal to kill the AU Riders and help them instead, starting the world mergers and setting off the Rider War.

Eiji isn't a killer either, the difference is Eiji can easily lose control to the Purple medals the moment a battle starts going south for him, removing his inhibitions.
Decade Violent Emotion has no explanation and it's not an actual form, and Tsukasa loses it anyway once he's resurrected.

I never said he was a killer....I don't think.

Another thing I was taking into account is that while OOO's can change into all the forms, once he does he is usually physically drained after he does that. Unless we are counting just his appearance in MegaMax, when they just happened to leave that part out and he could change whenever the hell he felt like it.

That's because at that point he found his desire, which is what the core medals are powered by. The reason why he kept getting drained early on in the series was because of his lack of desire

Hmm...I thought it still took it out of him. Oh well. Already voted. Not much more I can do.

Tru dat Decade, it's in the hands of the other voters now

Actually, by the halfway point (Around the time he gets the purple medals), he can form swap like crazy without it taxing his body.
In fact, many filler fights (Random fights against Yummies that have no bearing on the plot) in the later episodes would have him swap combos like crazy (Not Gokaiger transformation spam crazy, but still pretty quick compared to earlier episodes).

True. The combo fatigue thing is one of those little plot points that got thrown out/forgotten about down the road. (Much like having to enter and exit Mirror World from the same place in Ryuki :lol)