Below is the list of cities and stadiums already chosen for the Euro tournament, in order from highest capacity to lowest:
Remember it's a UK bid not an England bid, so the number of English stadia that can be used is limited to just SIX, with 1 on Scotland, 1 in Wales, 1 in Eire and 1 in N.Ireland. There nothing for Yorkshire, appreciate the capacities are too small but the FA could have thrown some money at it to increase the capacity of a Yorkshire club.
The stand out commissions are Anfield (choosing the new Everton stadium instead) and incredibly the Old Trafford is left out (choosing the Man City stadium).
Other more understandable omissions are the Arsenal and West Ham stadia, choosing Tottenham stadium.
So it's not a case of bigger the capacity the better, the FA have judged on quality of stadia, the more modern the better.
Also notice how Villa Park currently has a capacity of 42K, however they have guaranteed that when the tournament is played Villa Park will be increased to 52K.
The Man City stadium also currently has a capacity of 52K but this will shortly be increased to 61K by building an extra tier behind the goal, so the whole stadium become symmetrical. Also there are constant rumours that Newcastle are hoping to increase their capacity to around 60K too by building another tier behind the goal, so it's symmetrical on 3 sides (like Old Trafford) instead of the current daft looking 2 sides.
If the judgement is based on modern stadia with modern facilities to impress the corporate brigade and VIP's then of course Bramall Lane and especially Hillsboro wouldn't stand a chance with it's more traditional facilities, look and charm (traditional is a nice way of saying old fashioned).