Must have one more island, one less mountain. This increases the odds of being able to cast Delver on turn 1. Might even go +2 on islands.

That would suggest getting 1 or more mana accelerators for red, which i was thinking about anyway. Of most interest:

rite of flame 1-->2+
seething song 3-->5
desperate ritual 2-->3
pyretic ritual 2-->3

or if I wanted to go in different direction with splash of black as option:

land: sulfur vent  1-->2 (RU) once only (normally produces black)

Other cards of interest:

Manamorphose
Psychotic Fury
Betrayal
Rhystic Study