Adding new tiers, or changing how one is put into one.

FallenAdam

Essentially, the way the tiers work now, one can be "punished" for experimenting with one colour more than others. I've been mostly experimenting with Blue/Black decks as of late, and as a result, have been ranked in Platinum tier, while still mostly using the same deck I did when I got bumped from Silver to Gold.

Make the mechanic for deciding in which tier one belongs include something that would take into account, if one has a deck that can combo multiple mythic cards and kill ones opponent in a couple turns, or still uses more basic mechanics.

Mburn7

Technically you would only be platinum in events where there is a node with a color that you're platinum in.  So if you are only plat in black and silver in everything else than any event without a black node you would be silver.

The issue is Oktagon makes every event 5 colors (and most nodes multicolored).

I feel like an easier solution would be to go back to mono-color nodes in events, which would mean that you're only in platinum in events where you actually have a chance.

Just for reference though, people have been asking for a tier rework for years.  We've had ELO systems, card weighting systems, deck-by-deck analysis systems, or just the same system with higher tier-up thresholds all proposed and ignored several times.  I doubt any real change is coming any time soon.