so aside from ranged troops (i.e. ballistas), does anyone have any good strategies for combating these large blocking armies that some use (in non-skirm games)?

honestly, who wants to attack a stack of 72 heavy cav?

Well it is a tough call since it will yield way above 1000 in retal. but if he were to attack you it will only be limited to 1000 (plus level points).

So why not put two good stacks of mace to pin him down and put them in defense, do not attack, and meanwhile you let go with marks + comms. or even better tower.

Of course this sounds easier said than done, but you can direct your strike and create a gap between this and his main force, therefore isolating this stack.

yes, good in theory (not so much so in practice)

the other thing, is that it's not just the big stack of heavy cav, it's most of his melee armies protecting his stacks of ballistas.

so i was thinking perhaps fighting fire with fire, big stacks vs big stacks, but gaining the rps advantage. i don't know, i think i may just have to pull back towards my castle and act like a turtle hiding in its shell.

Shave them down with towers + marks + comms (but make sure you can hold them).

And avoid hitting in melee such a big stack.

yes, i left out that by fighting fire with fire, i didn't mean attacking, but blocking my own ranged, and hoping he'd break down and attack my melee (probably won't happen).

still have to have the money to produce said things

Just remember to use ZOC to your advantage.

You don't need a wall of troops, place them correctly and there can be gaps, but other players stacks can't go through.

And if worst comes to worst, retreat and regroup, but always keep scouting. This is an option that is seldom used, you gaing nothing for sacrificing your stacks (there is no moral stuff, nor nothing). Back out closer to your reinforcements, and this way you salvage and otherwise lost scenarios.

Doesn't always work - a gapped ZOC tactic fails when someone expends part of their attack to first widen that gap, THEN charge through with no ZOC problem

Yes of course, always reinforce potential strike zones, double stacking, and suchs.

Well, it sounds so very obvious, but you'd all be surprised how quickly that safe spot suddenly vanishes in a single battle game turn
And therefore, I suppose that should hold true for campaigns...but of course the mechanics are trickier, and you have more to work with (depending on your log-in rate, of course - once in a 2-turn/day game don't cut it )