The right side looks like a really nice balance doesn't it?
Ideally I'd like the same sort of options on the left, one a more defensive minded player that links up with the fullback, which I think can be Cleverley, and then a more attacking option. I really rate Kev but for me he seems better on the right and Martinez appears reluctant to give him much game time so guess he'll be off in the summer. Niasse may work but iirc one of reviews I read about him indicated his rapid improvement as a player coincided with a shift from the wing to the centre. Personally think we run Rom into the ground too much/play him when injured and think there is enough gametime to keep two good strikers content.
Martinez clearly has a plan for where he'd play Yarmolenko if he brought him, presumably left or central, but whenever I've seen him play he's been on the right and find it really hard to judge how well he'd perform in any other position.
I don't watch Mertens regularly but I've seen him play for both Napoli and Belgium in the position we require and do well so feel a bit more confident that he'd suit us. However think it unlikley he'd move as he seems settled and since he turns 29 in the summer a high transfer fee/salary to tempt Napoli and him would probably be unwise. With my sensible hat on there are probably better options, but he has such a sunny character and nice smile I'll likely still mention him until we get that side more established
How about you, who is your preferred option?