I think honesty, real honesty- with yourself, and the ability to be deadly serious (I don't mean gruff or terse) are madatory if you want to develop 'martial' effectiveness through your Aikido or Karate or whatever etc.
ask yourself- can I look death in the face and maintain a fixed purpose?
This is a tough call, most people aren't capable of answering it honestly.
I mention this aspect because most people (I am guessing) will focus on the 'martial' effectiveness of their physical techniques- and define this by whether there is anyone in their dojo that can 'defeat' their awesome [insert technique name].
I think this type of thinking is a mistake.
drilling your physical techniques is an important aspect of honing martial skill- but your attitude- not only to training, but to your life- the life you are responsible for preserving, is in my opinion a governing factor.
Soo...can you gauge your attitude in the dojo and apply observations from that analysis to your life outside the Dojo?
I think I can.
BTW, I am obviously not an acomplished academic or vastly experienced in Aikido- i am just offering my opinion to add to the discussion- so please don't come at me with that "you can't tell me about boats, I know bout boats!" malarchy. Just take it for what it's worth to you.
P.S. this is my deadly serious face