Water and Earth decks sort of seem to be the way to go as far as Bronze and Silver league go, so I think you should definitely hold on to Alric for that +1 magic buff. As far as mermaid goes, it's a hard hitter, but I think it's going to come down to if you're going to focus more on modern or wild if it doesn't get reprinted. Mylor has been an absolute thorn in my side to play against. No pun intended. I'm a bit too spread between every splinter except Earth and Dragon. There's a few dragon cards as well that feature thorns or just make great tanks in general, such as Djinn Chwala and Naga Brute.
From a purely investment standpoint, i'm looking at scooping up more of Phantom Soldier, Soulstorm and maybe Ancient Lich for the Death splinter as some relatively cheap/effective cards.
Thanks for your input. The thorns have been nice so far. I've had Djinn Chwala for a bit, but haven't used the card too much.