Hey, Watertrap Weaver is an underrated Merfolk. It's ability is good tempo what you want with Merfolk to continue to get damage through. 4x Unsummon is great, but I don't think it's enough main deck tempo to delay Midrange. Caller is also good although kind of slow because four mana is sometimes hard to get. Creatures pretty much rule Standard right now ordinarily Weaver's and Caller's abilities are not main deck worthy, but in current Standard they very much are.

I've found Jade Bearer, Deeproot Elite and Jungleborn Pioneer to be very lackluster. Both Bearer and Elite need ideal game situations to be good. Elite can be powerful, but it needs to come down before any other Merfolk which happens some games, but consistently not. It really sucks to draw him after emptying a hand of Merfolk. The three drop spot for Merfolk is very crowded Kumena is the most important, Jadelight is pretty powerful although double green casting cost is problematic. I suggest giving 3x Watertrap Weaver a playtest as the third three drop Merfolk.

Good luck with your deck.

I appreciate the feedback! I'll do some playtesting with the Watertrap Weaver.