Lukaku is an extremely good footballer but he is not great by any stretch of the imagination. If the team are playing well, Lukaku plays well but the sign of a great player is one who can lift a team and carry them when the rest are not performing. Lukaku cannot do that yet and has too many big games where he goes missing. Yes lack of support and creativity can hinder in the big games but he still seems to 'go through the motions' when the chips are down rather than rally and reinvigorate the team.
As for Ross, its almost as if he is unsure what type of player he is. Yes he will have purple patches but again there is a real lack of consistency to his game. As I've said before, Ross has all the attributes other than the footballing brain to be at the very peak of his profession. Will it come in time, i'm not so sure. He is not a young lad anymore and although workrate, effort etc has gotten a lot better since Koeman's handling early part of the season, his decision making etc is still poor at times.
If we were given a massive amount of cash in the summer, i wouldn't be too upset letting Ross go and also Lukaku to a certain extent, as long as that 100m plus was reinvested in top quality players.
This summer is a big one for the club. There are still a lot of areas that need addressing if we are serious on becoming top four contenders.