Brute: Spin, 6 damage/end.
Tank: Spin, 7.6 damage/end.
Widow: Spin, 4.75 w/50% of 7.93.
I assume the Tank numbers being higher with Fury not being factored in for a Brute. Widow has the highest end cost so it kind of needs that 50% to go off. Scrapper is over 10 damage/end without Crits factored in.
To add, recharge for Tanks, Brutes, and Widows is 14 seconds. End usage for Tanks and Brutes is 13.146. For Widows it is 15.444. Widows with the reduced end cost would be 5.9 and 50% chance of 9.31 which seems far more fair. It puts it in the range of 7.6 overall, which oh noes, it does tank level damage.