In cases like this, its easy to be caught up by reality, which is a poor fit for D&D.
Heh.
By this I mean simply that once you're off the very first level or two, you no longer die from a single solid hit, which was the point of the longspear - in real-life, hitting your foe before your foe hits you is extremely important, and often decisive. In D&D, this aspect is almost completely absent.
Well, those lower-hp/lower-CR monsters are supposed to stay relevant a lot longer thanks to BA, so it wouldn't seem so crazy on the player side - and on the lower-CR side, well, they fight eachother a lot, too.
And not only that. D&D wants an active, heroic gameplay. To achieve that, offense is always given preference.
If that were really the whole story, it wouldn't be so deeply into resource-management.
You don't want a rule that encourages people to hide behind their shields and spear walls - you want rules that encourages true heroes to jump in the fray with abandon!
Long spears and big shields didn't much detract from the heroism of the 300, nor from the archetypal knight in shining armor.
That said, being able to charge and deliver your full wallop of attacks easily becomes too good.
Not necessarily. The game does allow ranged characters, whether using weapons or cantrips to get in their full DPR ever round, and, for that matter a single attack/round character with competitive DPR from that one attack has no issue with losing damage as long as it can get in that one attack. Just letting the charger get his full DPR in some way would probably be just fine, to the standards of 5e 'balance' (ie, no worse than Sharpshooter, for instance).
On the other hand, charging and only being allowed a single attack is too weak (once you're above level 4).
Especially when charging someone else who also makes multiple attacks (it was quite the noticeably thing in 3e, really, contributing to the 'static combat' problem).
Of course, in TotM, static combat is arguably desirable. It eliminates having to track changing positions each round, supporting simpler, faster combat. :shrug:
