Dearest Xagu,
You are interpreting the rule correctly. The idea is that a Knight with a low Might cannot properly wield a giant talon. Meanwhile, Knights with high Might have a wider selection to choose from. The exception would be special items which you are able to wield due to the exceptional quality of the weapon.
If your Might is low, you will have a higher Agility, Presence, or Intellect. Therein lies your Knight’s strength!
I highly encourage you to hack the rules to make them most fun for your table.
Sincerely,
Jim Hall