Subtractive means you just have filters on the synth. Additive means you add oscillators or sound lines. FM means you multiply the frequency of one oscillator by the signal of another.
Wavetable uses a sample bank as an oscillator, that's all, and it can crossfade oscillaors it's super powerful because it can emply the FM sound-timbres from the FM and its'generally simpler to control and program. what wavetable can't do is emulate the effects of LFO on Frequency modulated sounds, which are pretty confusing even i dont understand them, i haven't studied FM8 synth yet it didnt seem worth the hype.
All good synths use filters so all are subtractive. all have multiple oscs so all are additive. FM synths come in two types... ones with a modulation index like FM8 and ones without. FM is very difficult to control and program.
FM doesnt create a wider array of sound, it creates more timbres for the same number of oscillators, but LFO's and additive detune are what actually create the real synth richness.
So with a given number of oscillators, FM can logically make more crazy sound, but in reality that doesnt totally play out, because you dont need a wide variety of sound to make good sounds. It's like using pixels versus using paint. both can do awesome stuff.
A synth is a technological barrier to your creativity, you can think in terms of how fast it is to find an array of sounds from a system, so as a practical tool for scanning alot of sounds fast and modding them funly, rather than something that with study can make more sounds... practical fastness and flexibility is a balance that is more crucial than depth of sound.