Dekkers wasn't the best in his weightclass, allthough he probably was amongst them. In his prime he probably was pretty the most dominant in Thaiboxing, at least European/modified rules. On full Thai rules, especially in the beginning in his carreer he got 'outclassed' by the Thais... with that I mean they were just better on those rules, Dekkers wasn't used to them also... Especially the elbows and clinches bothered them, and those are ofcourse important aspect in Thailand. Dekkers speciality was his boxing, which doesn't score as much.
Many people claim that he was robbed several times in Thailand, being it home-decisions etc... those are not true, at least most of them. It was just the rules. Allthough there are fights which he completely dominated with his boxing combinations, dazzled his opponent several times, but still lost. Alltough that doesn't seem right, it actually is, according to the rules. Sucky, but that's the way it is
Besides all that, there always is serious betting going on in Thailand, so you'd better not screw with decisions, because you then screw with the bets and the people! You don't want pissed off people losing all their money so to speak
About Hoost, well, you can pretty much say he's the best in the heavyweights, along with Aerts. Aerts is a bit underrated with Hoost, but both are extreme good technicians, with knockout power in every available technique (at least in their primes). Both have highkick, lowkick, punch and knee-knockouts... Hoost ofcourse didn't get the Mr Perfect nickname for nothing, and allthough he has 4 K-1 GPs won, and Aerts 3, I just want to place them on the same level of skill and achievement. Aerts actually won from Hoost when I consider them both in their primes (98).
It's always hard to compare fighters pound for pound. In lighter weightclasses you generally have less KO's, but more fast, technical actions. In the heavyweights it's the other way around. That's why Dekkers has such an incredible record: over 200 fights, 175 wins, 90 KO's. That's an extreme accomplishment. Even today his sparringpartners say he hits almost like a heavyweight. Dekkers in his beginning of his carreer was a relentless fighter, later on he became more of a relaxed tactician in the ring, just chosing he chances. See his comeback fight against Ludwig for example, of his former farewell fight against Marino DeFlorin. Just calm, picking his (incredible powerful) shots.
I don't want to pick none of them as the best P4P, and besides that, you just forget there were so many other great(er) fighters in Dekkers weightclass before... (Sakmongkong, Jomhod, Jongsanan, and the list goes on and on...)