Honestly, I don't think that Bruno Senna was ever given a good crack at it when he was at HRT. He was in easily the worst car on the grid, and was regularly out-qualifying his team-mates. Remember that he was lined up as a race-driver for Honda for 2009, but was only not signed up because Honda pulled out of F1. He is NOT a bad driver. All that can be said is that he lacks experience. Having a season behind him, and a properly funded seat in F1 means that he now has the opportunity to show his worth.
If he out-qualifies Petrov, then it will show his underlying talent. If he doesn't, then he should probably accept the inevitable and return to Brazil.