And the disadvantages of polearms are?
From my point of view they work against horses, have quite long reach but are capable in close combat too and in combination with a shield they can block arrows as well.
For the buckler, well you deflect the blows and donĀ“t block them, but this is nitpicking.
To block missiles is mostly luck (i know, archeres says something different) and with attacks from the sides it is the same.
If you want, i can use a huscarl or a steel shield as well.