Well... anyone can build tanky, so that's a moot point, imo. Being a tank is more about CC, which old GP wasn't either.
No engage, sure, but many champs don't. Especially fighters. MOST especially fighters with strong poke. It's fine. Also, old GP didn't have this either.
His R is great counter engage. It isn't Riot's fault if your team sucks and can't use it correctly, or if you aim it poorly. Not everything can be a skillshot. Again, neither did old GP.
Old GP; no hard CC.
His W is not primarily for healing. It's for removing CC. Old GP was similar. I didn't look at numbers before posting, but his old heal wasn't great either.
He may not have a speed steroid, but old GP's was clunky. It was a frequent, valid criticism, and the new barrel minigame is quite fun, and engaging.
I'm not sure what space you think he should occupy, but I seem to remember from the Riot stuff about it that he should be a good split pusher. Have you considered using R for global presence while you split? Using W and E to keep you safe while you do it, and Q to get even more gold as you approach late game? Seems to me that's where he would be successful. He doesn't need the tools you describe to be a good fighter.