You don't need tall WRs to score TDs.
The biggest improvement in scoring TDs is for the Bills to actually throw the ball into the endzone- preferably from outside the redzone.
Historically, the most TD passes are from the 20 -30 yard lines.
The Billls do not need the best players at WR and TE. What they need are the best playmakers available at their draft slots. They should not pass on playmakers on defense or a stud OL to take a lesser player just because he is a tall WR.