HF will always be Indy to me. Others may play him, but HF has, as he himself has said, made Indy his life's work. Plus all the humanitarian stuff he does, including literally rescuing people who are stranded, makes him seem that much more like Indy. But I have to accept the possibility, indeed likelihood, that they will try. So...
I like Pratt as Star Lord. A lot, in fact, and I love the riff they did on the opening of Raiders in the opening of GOTG. But I have a tough time seeing him as Indy (the very good Photoshop Gaith posted notwithstanding). An adventurer? Yes, definitely. A Rick O'Connell type? Oh yeah. But Indy? I'm just not sure he can bring the full range of being very, very book smart and also good on his feet and in a fight.
I'm probably one of Ingruber's most vocal supporters on here, if not the most, and I have long thought that he would be a very interesting (and cheap, at least as an experiment) choice, particularly if he had the chance to talk and study with HF (which he has now had for the film TMBTM mentioned). I don't know what he is like in extended sequences, but he does have fantastic range physically and vocally; if it could be harnessed right, then he could be a worthy successor to (at least) River Phoenix and Sean Patrick Flanery (not counting Corey Carrier here, since his "Kid Indy" was a little too different and underdeveloped to compare). I do plan to see Age of Adaline, almost solely for Ingruber and HF, since (as easy as she is on the eyes) I usually can't stand Blake Lively.
Having said all that, there are two known actors I have considered as possible Indys. A number of years ago, before KOTCS, when it looked like they might try to recast, I realized that Dennis Quaid could probably do it. He has always had many HF-like qualities to his acting, and he has aged to look increasingly like him. But at this point, he too is probably older than they would want for a reboot.
The other actor is someone who is much younger -- not quite as young as HF was in ROTLA, but not much older, and he looks younger than he is, as HF always has. He has a similar voice, is in great shape, is incredibly smart in real life and can "play smart" on camera, and he also looks like he can handle himself in a fight. He also currently plays a guy who will stop at nothing once he has his eyes on a prize, and he's even got the Jewish background and features HF does (though in his case, both his parents are Jewish, not just one). He doesn't have a broken nose or a scar, but those are easily added, as the scar on Flanery proved.
Who is he? Gabriel Macht. I honestly never, ever thought of him as Indy before, but something about seeing him on Suits last season and (maybe more importantly) reading an interview with him where he talked in part about how he prepares for a role made me realize that he builds lots of subtle layers into his performances, much like HF does. And in this photo, at least, he even has a very young HF vibe:
He might not look as much like HF as Ingruber does, but if they're determined to recast, they could do a lot worse. Hell, do both -- Ingruber for the years between The Scandal of 1920 and ToD, and Macht for the years between LC and KOTCS.