I feel like it can be a good play in the right meta, especially with all the fire stuff taking over, a la pyroar/mega char decks. heres my current list:
3 Squirtle
1 Wartortle
3 Blastoise
3 Keldeo EX
1 Blastoise EX
1 M Blastoise EX
1 Greninja EX
2 Suicune
14 Water
4 Sycamore
4 N
4 Skyla
4 Ultra Ball
4 SER
4 Candy
4 Letter
2 Bicycle (gonna replace these with megaphones)
1 Scoop Up Cyclone ACE SPEC
I know a lot of people would laugh at this list, and im not a supercompetitive player, but i took this to a prerelease and 2 leagues and im 6-2 with it so far, so its doing really well. My wins were over Klinklang, RayBoar, and 2 wins over Pyroar as well as a mirror match win. So the deck def isnt dead by any stretch, and theres ways around beach. maybe Delphox would work here simply as a 2-2 card drawing tech? Obviously you wouldnt be attacking with it, but the Mystical Fire would still help, who says just because it's fire that you cant play it in Blastoise? Oh, and the Mega is way better than most people think IF you know how to build around it. At least IMO, but youre gonna get naysayers. So take from that what you will.