$20 and change per character to cap duty officer roster space seems high, in my opinion. I'd be more tempted if it were per-account, or a quarter the price. I say this not as criticism, just to let you know that you've priced it out of my range.
Why would you need more duty officer space?
More doff mission space would be something and would make a need for more duty officer space but...
Well, as someone who will be buying more let me run some numbers past you.
Different specializations: about 45 (don't remember the exact count minus the pooled ones like refugees and prisoners that don't go against your count)
Some of the speicalized missions require 2 of a specific type, and many of them you need multiples to increase your success chances. (Granted they don't always have a single type, but 3 officers of 2 types and other combos for 4 and 5 are very common)
If you want to run multiples of certain types of missions you need way more than 2 of those types (traders and quartermasters are notable here)
There are all those green and better ones you can buy from Frerra.
I have been capped for a few days now, and choosing which white was least necessary was getting really hard. I definitely need at least 100 more, and I will probably be getting all 400 eventually.
I understand that it's for getting excess numbers of the "right" specialties but seriously??? It sounds like the following:
a) kind of P2W to me
b) kind of superfluous since it's very easy to get to 4 in the long term
c) it bestows no advantage
d) it's more than a stipend.
I am going to buy some DOFFs and additional DOFF space, not because I need them, but because I want to show my support to Cryptic for the hard work that has gone into this part of the game.
I would have been happy with much less than what the DOFF system has now become, but because of Heretic's hard work and constant attention to detail (and listening to feedback) it has become a game in its own right, and helped make STO a better overall experience.