Though spells and abilities that are exiled won't get a chance to resolve, they don't count as being "countered." If Sundial of the Infinite's ability is activated before the end step, any "at the beginning of the end step"-triggered abilities won't get the chance to trigger that turn because the end step is skipped
Turns out, not that many people prepared for Chancellor of the Annex
Oriq Loremage is one to consider putting in your decks that care about your graveyard
You also get to put a counter on a creature whenever you draw a card
Oh, hello there, cornerstone of every Flicker deck from now on , how have you been
That being said I'd keep this card for slower formats, since it'll take at least two turns before it outputs more mana than it takes to activate its ability