Yes, about that.
OJP and MotF before that spent a lot of time on the saber system problem. In fact, you'll see several tome-sized threads in both of those forums about the saber systems.
Anyway, about manual blocking, my experience has been that it just doesn't work very well in JKA/JKO's fast paced saber combat simply because the player could have manually dodged the attack if they had the forsight to react. My work with OJP experimented with both manually directed (like in MB2) and button timed based parries/blocks and I didn't like the results for either.
Currently, OJP uses a autoblock/movement-based parry system, where the blocks are automatic, but players can do parries by moving into the attack while walking. I think that's the best solution I've seen so far.
If you're interested, you can download the latest OJP Enhanced beta from ojp.jediknight.net. OR if you want to try a manual blocking system, try
www.moviebattles.com).