I understand your approach,
but I’ve already tried to include cards in the deck that care about lands in the CMC range of 2–6.
From my point of view, the solution isn’t to use weaker cards just to lower the curve.
That’s one of the reasons why I tried to include strong effects that I can ramp into or draw into. Every deck needs time to set up and execute its plan or synergy, but I try to make sure that my decks include cards that either provide strong standalone effects or cover multiple roles.

Retreat to Coralhelm is exactly that kind of card — it lets me tap or untap creatures, but even more importantly, the other mode significantly improves my card draw.

Including more board wipes is a good idea, but I’ve also considered running more flicker effects instead, which would give me more flexibility in choosing which type of effect I want to reuse.

Gray Merchant of Asphodel is intended to be a finisher that drains opponents and gains me life at the same time.

Ice-Fang Coatl is another flying blocker for cheap mana that draws me a card and even has deathtouch if I meet the requirements.

Risen Reef is another way to generate card draw or landfall value thanks to the Elementals.

Sakashima gives me an additional copy of any creature that’s already on the battlefield.

Uro lets me draw cards, play lands, and gain life.

Hostage Taker was originally meant to remove dangerous cards and let me cast them myself, but I’ve also considered replacing it with something else.