i'm far from experienced, unless you count all the times i've been run over!

the irish need to move fast and overwhelm their opponent. look to the 100 man units of bonnachts, four or five or six (the sheer numbers makes up for the penalty of taking more than four units imo) of them out front will send the archers packing and damage the huscarls enough with their throwing spears for the a/p gallows to mop em up. depending on how many you take and how much valor you give the bonnachts, they can stand in the melee similar to celtic warriors. they are good arrow sponges too.

horsies are nice to to keep yer flanks safe. light horse at v2 has enough morale to put a hurting on already withered huscarls, especially if you hit em in the rear...

elmo and i have worked out a fairly decent irish swamp/rush army, where we both bring the tatties and swarm one or two poor unsuspecting opponents uphill of course...