Spears, pikes and rank bonuses

[Morindin]

. Once disordered or flanked it crumbles rapidly.

As it should do.

and slower to kill from side and rear

Absolutely not. One small Roman unit that broke off and hit the Macedonian rear in the battle of Cynoscephalae routed the entire Macedonian line.

Besides, I have no idea what you're talking about, I had a unit of Poeni infantry completely surrounded by Principes and man it took a while for them to die, over 10 minutes. Infact it got pretty boring after a while. The problem isnt they're easy to kill, the problem is 90% of the AI generals suck and their units have extremely low moral, routing quickly.
Once they rout that's it, and as you can see from the battle of Cynoscephalae, that isnt exactly unrealsitic either.

And those cretan archers will shred most phalanx in just a few volleys at extreme range. (It is entertaining, but not historical.)

Elite archers ripping up a slow moving unit of Phalanx's. Gee, how odd. I've had soooo much experiance with this, and usually the AI disrupts its line so you end up with 4 units of archers firing at one unit of Hoplites, which is no surprize.
But in a 1v1 situation one volly of arrows will kill 1-4 of them at best.
I've had one unit of Archer Auxulia pretty much waste all its ammo on one unit of Poeni Infantry (just sitting there mind you) and only killing about 10% of them - but when you gang up 4 units of elite archers onto one unit of hoplites though, literally peppering them with arrows, what do you expect?