I'm not talking mega-goals, but 7,8,10 a season or so.
I don't think these players are that rare. Even that carthorse Andy Carroll knows where the goal is.
We keep seeing in Lukaku threads that he needs to improve his hold up play and his physicality generally as people feel these should be pre-requisites for strikers of a certain size. I'm not that keen on the Heskey-style 'big lump' forward who never scores but 'makes the team better' because ultimately you have to sacrifice something to accommodate them in the lineup (in this instance probably Barkley to the bench).
Ah, fair enough.
Given those numbers, I don't think Belfodil is terribly far off what you're talking about. When he's been used properly, he's pretty much hit those targets -- 8 goals for Parma in Serie A and 6 goals in his half-season at Standard. Sure, it's not particularly inspiring that he went into the wilderness for a few years but that sort of thing can happen to a young player. If he gets minutes at Everton, I think his goal return will be somewhere in that 7-10 goal range (over a full season's worth of games, of course). Koeman's teams play a lot of crosses and Belfodil appears to be pretty good on headed attempts. That alone should be worth a few extra goals.
I don't think anyone is arguing with your second point. A big lump that's only there to win flick-ons and hold the ball is too big of a sacrifice in today's game, especially given how much the quality of play in the PL has improved over the past five years. The reason I think Belfodil will ultimately be okay is because he's not just a one-dimensional workhorse. He's also a good dribbler and, according to some Standard supporters, is very involved in their build-up play as a passer. I watched a little bit of the Standard/Dortmund friendly today and, in the instances where this guy was able to get on the ball (Dortmund suffocated most of the meaningful space on the pitch for the majority of the match), he really does glide with it. Not that he's a particularly brilliant technician or anything but I wouldn't write off that aspect of his game.
As for Belfodil potentially keeping Barkley out of the team... I would be slightly concerned about this but it does seem like Koeman is making an effort to find an alternative role for him. Ross has been asked to play a bit wider during some of our recent matches and he's actually looked quite good. Under Martinez, it seemed like Barkley was asked, or maybe just forced by the opposing team, to hug the touchline and try to run at players, which he wasn't very good at with the sideline as an extra defender. Under Koeman, he's played the wide position more like a Pienaar/Osman, drifting into the half-spaces and making use of all of the options that he has in that area. I think (and maybe this is a bit wishful) that Belfodil is more likely to keep Lennon/Mirallas/Valencia out of the team.
I'm not 100% sold on the move either (there's a very high risk of failure for this guy) but I'm very intrigued by the prospect of what he might bring. Part of this is me imagining us becoming a supercharged version of Moyes' last Everton side, with a superior midfield (Gana/Schneiderlin instead of Neville/Osman/Gibson), Belfodil playing a Fellaini-esque #10 (with a little extra flair and hopefully less petulance), Barkley as a Pienaar-type wide player (minus the foul-winning ability/telepathy but with added dribbling/shooting powers), and Lukaku as a better forward than Anichebe, Jelavic, and Vellios combined. Maybe it's a bit ridiculous to hope for all that but I don't think it's totally unreasonable.
(The only problem with the aforementioned team is that the backline looks awful compared to what it was in 2012-13, minus the much improved Coleman.)