Do you think Schizo waves are easier or harder than mono waves? If you think they are harder, then I'm not sure what more I can say to convince you otherwise. If you think they are easier, then you should realize using roles over types pushes a wave more towards the current, easier, schizo waves, and worse, it does so mainly for the harder AI Types. Of course, this means you'll say you don't think Schizo waves are either easier or harder.
Depends if you mean average difficulty, min difficulty, or max difficulty.
Average difficulty for schizos is very slightly higher than mono waves (as you can no longer minimize losses by sending in one counter).
Min difficulty for schizos is higher than min difficulty for mono waves (imagine the "terror" of a shield bearer mono wave.
) In fact, the min difficulty for a schizo wave is only a little below average difficulty for schizo waves.
Max, practical (as in, restricting to loadouts you can expect to see in any sort of humanly possible playtimes) difficulty for schizos is much lower than max difficulty for mono waves (due to it being far less likely that the AI will spam ships built for offensive, "take out the planet" actions, like they can and will do with mono waves). This is because the max, practical difficulty for schizo wave is only little bit higher than its average difficulty, where as the difference between the average and max difficulty mono waves is quite large.
Max difficulty for schizo waves, if you include those extremely rare chances of getting certain loadouts (I mean rare like like 1/2^50 rare), are actually HIGHER than max difficulty for mono-waves. (Think munitions boosters, shield bearers, zombards, bombers, and maybe something like a Spire railcluster, plus a Spire starship and/or a plasma seige starship to deal with any grav turrets and a raid starship (self explanatory), in proper ratios for the support style ships to properly support the offensive ships, but still have enough offensive ships to be threatening. Very, very rare, but possible, and will be a nightmare if you do face a good sized wave like this)
EDIT: This is one of the reasons why I suggested that the AI would sometimes use role based ship selections, so it would actually try to aim for things like this, so they happen more often than once every lifetime. It could try to build a loadout of support + anti-structure + long-range. Or it could try other clever "role mixes" that could prove to be very scary (tractor + melee, tractor + support, cloakers + high-capped ships, long-range + support + melee, etc. All sorts of fun possibilities.)