I only think Bebo is where she is today because she's been given chances over and over again to improve herself. If you give a person time, obviously he/she's going to get it right the 50th time or so. Had it been any other actress coming from a non-filmy/ordinary family background, am sure of the exit she would receive after 5 movies at a maximum. That said, I wouldn't want to snatch away all credit from her, she's worked hard no doubt, coming from performances like Main Prem Ki Deewani or whatever, to a very critically acclaimed Kurbaan. I won't cite Jab We Met because I personally found it a bit over-the-top, though her skills in the latter half were commendable.
Deepika, on the other hand, is mostly where she is today due to SRK and Farah Khan's success. But she's working towards becoming better, I don't deny that. Though I still don't find her anywhere near a good actress. She's beautiful and has the right figure yes, but that far from makes her able to take Bebo's place right? She's got a lot to work upon, and fast if she wants to stick around with the kind of talent coming up.
On a side note though, I feel each actress has her era, you cannot say it's Rekha, or Hema Malini, or Rani, or Kajol's time today even if once in a while they may come up with brillant characters in today's movies. I think there's a time when you shine, and after that, people go and watch you because you were brillant and would always remain for them.
I think Priyanka's way better out of the current lot. If I would compare, I would seek someone who could take her place truly. She's brillant, started at such a young age, and had no real family backbone to support her journey throughout. She takes chances, does movies she believes in and makes the character believable. She's the only one right now who makes me wants to watch a movie just because she's in there, like Rani or Kajol did at a time. That's called being a true actress for me. π