As the S8 won't have a removable battery or IR those are debatable, and not everyone wants larger. Indeed LG will tell you that they chose the size of the G6 as a result of extensive market research.
I think the one lack of "future proofing" in the G6 is the 32GB storage (unless you are in Asia, which illustrates the stupidity of their strategy for this phone - we all know there are better versions which they think we don't want. I contacted them to tell them they cost themselves my custom with their regional strategy, just because I want them to know that these "local" decisions don't work these days).
People will say "it's got an old processor" but frankly that's not going to make any real difference to anyone but spec heads, and it remains to be seen how the s835 really performs (in real use, not benchmarks). Put it this way, I always buy flagships, and right now I'm considering buying one of last year's rather than bothering with this year's models. The truth is that we're pretty much at a plateau with these devices at the moment. The new screen format is the one interesting development this year, and I personally prefer flat to Samsung's curved edges (others may differ, but to me a flat screen works better, and that is what matters). That's why everyone is jumping on the "AI assistant" bandwagon this year, but if you want that then you can have the Google one on any recent device so I don't see that as a selling point for anyone (and Samsung adding a dedicated button for theirs would just annoy me - I'd have to root just to repurpose it
).
So personally I'd say that apart from being better with more storage it's actually as "future proof" as anything out there.
Will it be able to compete is a different question. Samsung's marketing budget (which includes incentives to promote their devices as well as simple adverts) exceeds some of their competitors' turnovers, so I doubt that anyone will compete on sales. But I don't see why anyone thinking of buying a phone should care about that: what matters is whether a particular phone appeals to you.