As title said.
Minions have no direct impact to gameplay, but still consume same quantity of relics as spells and gears, which make them the worst investment, even worse than spells.
Advise: Reduce the relic a minion required to evolve.
e.g. one T1 to rare, one T2 to epic, one or two T3 to legendary, and two T4 to mythic.
Reduce the glyph cost if possible is also welcomed…
Side thought: Strength is a quite meaningless minion stat. Give it a remake or improvement if possible.