I don't know how you can be so sure of this. Did you know when Dier was moved into DM that he would be a success? When we signed a teenage CM from MK Dons, did you know he would be one of the first on the team sheet six months later and an England international? Did you know Kane would turn into the goal scorer he has?Hernandez has already not cut the mustard in the prem. Berahino would need a month to get up to speed and Rhodes is never good enough in a month of Sundays.
I can only assume you knew all of this, otherwise there's no way you can be so sure that potential new signings will be a failure.
It's great to demand names from people before looking for negatives in each one. However, we don't know who is for sale, which clubs that might take an offer, which players have been promised moves, how much money we could spend, etc, so theoretically every player is up for grabs. I could mention Cavani, but you may reply that he would cost too much or be too old, but you've no frame of reference for that. Just opinion. Same as others want a striker to sign. Just opinion.