Is enchanting five pieces of armor with 20% chameleon considered cheating?
Well... most technically, since it's a single player game, it's impossible to really "cheat." Some might argue that you effectively "cheat yourself" by using gimmicks like 100% chameleon (and I'd tend to go along with that), but that's a somewhat different use of the word "cheat." "Cheat" implies that what you're doing is dishonest, which it isn't really, since you're the only one playing and you know that you're doing it and it must be okay with you or you wouldn't be doing it.
But 100% chameleon does diminish the game experience, in my opinion. To me, a good part of the point of playing any game is to challenge yourself and succeed, not because you learned some gimmick to use to give you an advantage, but simply because you possess the necessary skills to succeed on the game's terms.
For instance, just the other night, I finished The Ultimate Heist with a recent character. He made it all the way through the palace, in and out of the library, then back out of the palace, without once getting caught, relying entirely on sneaking skills-- no chameleon and no buffs of any sort. He made it because he moved slowly, kept track of the guards, stayed in the shadows, hid when he had to and moved when he could. That was an accomplishment and was very satisfying. It couldn't possibly have been anywhere near as satisfying if he'd first done some enchanting, then had just brazenly walked through the place. That, to me, would've been just as dull as walking through the Market District.
And to me, the same holds true for pretty much any similar things-- pretty much anything following "100%" -- 100% spell absorption, 100% reflect damage or reflect spell, 100% resistance to magic..... I just don't see the point in fighting something that can't hurt me. There's no skill involved in beating an opponent who can't hurt me anyway, so there's no satisfaction in doing it. For that, I might as well just open the console and type "kill."
For that, I might as well not bother playing the game at all.
'Least that's how I feel about it.....