Last night I got a bit disheartened playing offline against a friend and switched to Ryu because the invincible frames on m.dp allowed me to interrupt pressure strings. I left my friends house thinking it was time to drop Gief entirely due to him being forced to just sit back and accept any pressure thrown his way, until I realised that he does have a readily available way of interrupting strings and turning the tide: his v skill.
Success with this will require a huge amount of match up knowledge, and does come with a degree of risk, but when I considered that invincible reversals can be baited too, I realised that the risk is about the same for Gief but with a greater potential pay off. A DP gets you damage, but no mix up. A successful V skill parry with Gief is a mix up in itself. Will you just parry and then grab or will you tap forward to get the hit? And after the hit, will you grab or go for pressure (possibly the c.lk-c.lk-CA confirm? Haven't tested the ranges yet to know if it'll work)?
I don't think that widespread use of this tactic will change people's perception of Gief and move him up the tier rankings, he still has his problems with things like lariat's hit box that denies him any real hit confirm pressure, but the study needed to make it work will make you a better, more knowledgable player in a way that will benefit every character you play.