If there was absolutely no cheating, Putin would have won the elections anyway.
I think of two main reasons:
1. Effective propaganda: there was no day without TV showing Putin concerned about Russia or doing something for the benefit of Russia.
2. Lack of promising competitors: most people are sick and tired of Zuganov and Zhirinovsky. Other candidates are also not good enough. Mironov seems like a pale shadow of Zuganov, Prohorov can't win because he is an oligarh and his participation in the elections is perceived by many just like a whim of a rich person.

I think that the results would have been more unpredictable if, for example, the communists were represented by Sergei Udaltsov (his photo on Wikipedia is full of revolutionary romanticism ; BTW, he is a great grandson of famous Bolshevik, member of RSDLP since 1905), Grigory Yavlinsky was not declared ineligible to participate in the elections, and there was Alexey Navalny running. But I think Putin would have won this time even in this case - just not so gloriously - because he is really popular.

The thing I hate most of all is the increase in the duration of a presidential term from now on.
I want to elect new president every 4, or maybe 5 years - but definitely not 6! In my opinion, it's too long...