I have two alternatives that might be a little against the grain. Recently a very good pally I know switched to +15 str enchant this is equivalent to 30AP, the rationale for this is that the chant is always ON! and gives consistent DPS.
The other not common option that I am only mentioning for the purposes of theorycraft is +9 weapon damage. As you know "Rend" deals a percentage of weapon damage so a +9 weapon damage chant and a heavy weight stone +4 (can't be applied to BoA) is 11 extra weapon damge for a high end damage of 104.
Those were the two^
might also consider:
Fiery would be good for the double proc burst damage and fiery does proc more than crusader, if you are doing any pvp might want to consider this option as well.
I'm not a big fan of +25 agil on this weapon +25 agi offers more crits but they will be smaller crits.
Crusader is currently my personal favorite and the reason this enchant is so good has to do with it's unpredictabile burst damage that can blast through heals and over power opponents.
Recently I dueled my paladin friend me with crusader him with +15str. He won all of the duels where my crusader didn't proc, and often when it would proc he would simply avoid me and kite me around. Remember that if crusader is not proccing it is as if you do not have a weapon enchant at all! But when it does it is unmatchable