@Rex : I personally dimension LAC in bad PSR situation, though if you are thinking of a particular cell, check for MTC Count, LAU Attempts which should not be very high, if they are unusually high in case of border cell, increase CRH. PS: LAU will effect Paging.
Enabling Dynamic AG preemption is OK. Concentrating on PCH is better option. How much is the traffic in the LAC/MSC you are talking about particularly MTC Traffic & what is the equipped erlangs? If possible float BHCA & CCCH Config with current paging type being used, it must be TMSI though..