Sigil ?
Might affects both power and condition damage. The superior sigil affects only Direct Damage which is related to power damage only.
5 stacks of might will increase power damage by 175 at level 80. With the sigil, there is a 10 second cooldown and it gives 3 stacks of might for 20 seocnds. Theoretically you could maintain 6 stacks of might, but in practice you will also only have 3.
http://wiki.guildwars2.com/wiki/Might
As a percentage of your power, that has to be a big percentage, more than the 5% from your Sigil of Force. Plus of course you get the condition damage increase too. You can test the different effects to be sure in the Mists on the practice golems.
Since you do not have a cooldown on the other sigil, you don’t need to worry about sharing cooldowns between sigils.
Cleansing water triggers everytime you grant regeneration. Generosity has a 10 second cooldown to transfer one condition. That is a big difference if you count the regeneration procs you have in your traits and skills, but that is not an answer. Imo it just depends on whether or not you feel you need to have more or less condition removal.
Cleansing water has 5 ICD vs Generosity with a 10 ICD that only activates on crit.
Now, as for the Battle, more often than not you will have more than 3 stacks of might ,provided you are using your blast finishers, or you have more boon duration in your runes, or both. So, as stated above, it will contribute to your damage a great deal of the time.
If you are looking to switch out a sigil for Generosity, then your only option would be to take out Battle. The reason being is that Generosity and Battle share ICD which means using them together is a no-no. See, when one goes on cool down, both go on CD. Imagine cleansing a one second cripple with generosity. Now you can’t use Battle till after the 10 ICD.
In my opinion, if you really want more condi clear, grab cleansing fire. Otherwise, you should be fine with attunement swapping and dodge rolls.
http://tinyurl.com/oaxdkgt