Just to be clear I'm not expecting to see Luffy and Coby teaming up to beat Blackbeard in the final battle or anything, I'm saying that I actually expect Coby to eventually become THE marine to look up to, just like what Garp is right now, and in a similar way that Luffy is looking to be THE pirate in the same way as Roger.
So basically I know that doesn't necessarily mean that Coby/Luffy are going to have the exact same dynamic that Garp/Roger had (so maybe this whole discussion was a bit of a missunderstanding :P), but I think Coby is going to become the succesor of Garp's ideals as a marine and will accomplish an actual change in their structure and way of thinking, in a very similar manner to Luffy and the Strawhats being able to accomplish whatever Roger wasn't able to do when he reached Raftel (which seems to be sort of the implication based on what we've heard from Rayleigh), so that's what I mean when I'm talking about parallels.
Well if that's what you were really getting at, then we are more in alignment there.
When I say he's not the next Garp, I wasn't talking about his ideals, or even a theoretical teamup against Blackbeard, but more his relationship/dynamic with Luffy, how strong he is (I think at best he'll be an Admiral in the epilogue), etc.
I agree that the narrative supports Koby one day being in a position to help reform the Marines, or something along those lines. Though even with that, I just don't necessarily view it as being synonymous as being the next Garp, as Garp hasn't really expressed a desire to do that. Koby, Smoker, and Fujitora (maybe Drake and Kuzan too?) are the only Marines where I would classify them as wanting real change within the Marines. Like Garp's a good guy and all, but he's been kinda helping to uphold the status