Reg-ass is the only competitive O&C deck imo. Val is too slow (or too inconsistent depending on build), kim underpowered, and max eater keyhole drops from like 70% winrate to 30% when the corp opponent understands the matchup. I can see Val with 3 SMC 3 clone being good with Clot.
Tier 1.5 makes sense to me. It means either a deck with mostly tier-1 matchups but one or two particular opponents that it stone loses to (PE vs FF crim, gabe vs blue sun, HB rush vs RDI shaper), or a deck that's only slightly underpowered (I'm coming to believe reg-ass is here). Tier 2 either relies on unskilled opponent play, has 2 or more unsalvageable matchups, or can't mitigate variance.
Tier 1 corp: NEH biotics, NEH biotics+grails, BS glacier (with crisium), RP, RP grails, HB IT dept (ignoring time limit problem)
Tier 1 runner: Calim kate, stealth andy, andysuckers (with or without switchblade), leela (maybe??)
Tier 1.5 corp: HB FA+rush, NEH scorch and/or midseason, NEH ToL, BS glacier (without crisium), tennin
Tier 1.5 runner: Reg-ass max, parasite gabe, leela (more likely imo), stealth shaper
Tier 2 corp: HB CI, supermodernism (any weyland), Titan ToL, Argus shell game nonsense, Jin PE, NEH DRT, foundry grail, Jin IG
Tier 2 runner: Noise, max eater keyhole, valencia