Comments on bwangeroo’s deck:

Overall I think it is well thought and it’s probably the best fair non-blue thoughtseize deck.

However I don’t think the half way splashes are good. Double coloured spells are already sketchy in a deck with 5 colourless lands without splashing. 11 sources is decent but still a bit concerning. Relying on 1 dual to cast your delver with hate card seems very sketchy to me.

Three opinions of mine:
You need a very good reason to not play fow and brainstorm in a fair deck. You aren’t playing Thalia, a fast combo, or chalice. Thus the only reason DGA is not just bad Esper stoneblade is a better manabase, which you have lost with this build.

Meddling mage is good but it’s arguably worse in fair mus than Tidehollow Sculler or Kitesail Freebooter and not much better in unfair ones. I don’t think it’s worth the splash just for that card.

Decay is good vs delver, but basics vs Delver are better. Vindicate or Skyclave Apparition are both legacy playables.

I think you should either make the cuts above so you can run basic plains, castle lochwain and prismatic vista.
Or accept you have a sketch manabase and play Esper fair blue (stoneblade/vial/mentor depending on whether your favourite card is sfm or soulherder or mentor) for brainstorm, ponder, force of will which are better than any of your sideboard cards.