Actually, every mon can be fixed without Mega-evo, even things like Pidgeot. Hell, probably every fully evolved Pokémon from PU could be fixed.
Possibilities:
- Retcon typing (adding Fairy, for example): Bad Pokémon could get a better typing, though restricting to only adding Fairy-type to some Pokémon is sufficient.
- Intrinsic Abilities (Gameplay mechanic change, and thiswas what I hoped for when they talked about the "scoop of the century"): These could add a plethora of resistances to now-low tier Pokémon without interfering with their normal Ability.
Imagine Overcoat, Thick Fat and Levitate becoming intrinsic (for example Ice Body + Levitate Glalie). Or Overcoat giving resistances to Ice, Water and Flying. This gives far more flexibility than silly Mega evo's or even retconning typings since more Intrinsic abilities could appear, or they could even stack up and give 9-10 resistances to certain Pokémon alongside their current typing, giving now NU Pokémon a niche in OU.
- New abilities: Just give Pokémon that have pathetic abilities now in NU a better ability.
- Ability buffs: Pokémon that are designed with a bad ability, like Slaking, still have a NU placement and even in NU they aren't that threatening. But if Truant recovered health every resting turn? It would be much harder to deal with.
- Movepool size: Some Pokémon need more movepool additions than others. Some are obvious (why Escavalier didn't get Wild Charge is beyond me), and for some Pokémon new moves need to be designed - even if only carbon copies of already existing moves (just with a different type). Coverage is coverage.
- Move buffs/Nerfs: Some moves affect the entire meta, these could be nerfed directly (Lookin' at you, Stealth Rock) - or indirectly (Evasion boosting moves could be nerfed with more and more powerful moves that never miss, as well as retconning Roar and Whirlwind to never miss).
- Pokémon-specific items: If all else fails, this is something to be used. Megamons probably function already a lot like this, but do they really need a new fancy look and a really stupid name? (Mega-*insert Pokémon name here* What the hell). These items should not always only boost a stat (like Thick Club or Light Ball), but could for example also act like Light Clay and Leftovers in one (Things like Ledian would like it).
With these tools - which were already used before outside of Intrinsic abilities - was there REALLY need for Digimons Megamons? The answer is no.
Also, oddly, I doubt the Megamons marketability. Neither of them look truly marketable to me compared with their original forms if you ask me, and I have the feeling most will only appeal to boys aged between six and nine... which isn't a good idea considering how big Pokémon's target audience and fanbase is.
