First to agree that DUB facilities are deficient, blame the DAA and no one wanting to pay for anything for the last thirty years but....
The walk to 335 is less than the walks than the further out 400 pier gates.
There are about 20 short haul Gates on T2, 10 if they are used as long haul gates. There are far more morning EI departures than that so not every flight can be on the T2 pier, it was always meant to be like that. The CBP area and function ties up a lot of T2
Lots of airports (ARN, CPH, MAN) have interconnected terminals.
The terminal you see on your boarding card is the one you check in in and collect your bags from on arrival, not the boarding gate.
Fully agree that the South gates set up is very poor.