The problem here is that you're asking us to do field testing for something that can easily be verified just by looking at tooltips.
Why would we run any number of O1S's to test this and subject the results to composition, crit RNG, player performance, etc.?
The point is that the difference is extremely small, almost unnoticeable, to the point where even something like the aforementioned crit RNG would mask it completely, which is part of the problem; this is why people are complaining. Naturally gained Bloodspillers cause your PPGCD to actually go up by an appreciable amount, whereas TBN-proc'd Bloodspillers barely change it at all, and are either an extremely small loss, or (more rarely) an extremely small gain, to the point where TBN may as well not even do anything other than provide the shield. Every single time you use TBN to proc Bloodspiller you could have easily used that mana to DA a natural Bloodspiller, a Souleater, or even a Syphon Strike, and your PPGCD would be the same, if not slightly higher... for all intents and purposes it wouldn't change at all. Its a goddamn zero-sum game and that's why people are complaining.
If TBN was simply a 10-20% shield that cost no mana and had no blood gauge generation attached to it, DRK's DPS floor/ceiling would statistically not move at all.
