Getting Milotic is an adventure in itself. You have to Surf the water, climb the Waterfalls, Super Rod the tiles and then catch the Feebas. But even after this very arduous task you're still only half way there. Because now the makeover arc commences. You have to clean it, turn that frown into a smile and polish those scales until they shine so bright that even the sun gets blinded. And when that is done, finally the magical girl transformation happens!
Alternatively you can evolve it by trading but that's boring.
And then it's finally time for the
torunament contest arc. Sweep the competition and faint the jury with absolute beauty. Afterwards you can continue to do the same with the league.
When you're finally done all that is left is to box every other Pokemon, because why would you even need them at this point?
But jokes aside: It's a cool Pokemon and getting it feels like an adventure. One that feels rewarding to go through.
What are some of your favorite methods of evolution for water pokemon?
Other than the ones you already mentioned I actually have a hard time coming up with others.
I have been thinking about Magikarp, however; especially the way it evolves. I'm a little bit disappointed, to be honest. For Magikarp it's supposed to be difficult for it to evolve. Thinking about it, the only generation where getting a Gyarados felt difficult was gen 1, though. The reason for that is the reliance on switch training and the EXP-Share being locked away for a long time. In every newer generation it just felt easier and easier to get. Just put Magikarp into the party, activate the early EXP-Share and let it do the rest.
I think Magicarp should be able to learn Waterfall. What's more: it should evolve only when it knows the move. However, to make things difficult learning Waterfall doesn't involve the HM/TM. Instead there could be a quest involved, one where you can unlock a way that can still be access for other Magikarp evolutions later on.
