I dont think much would have changed other than the small details such as extra features that PS3 brought - Wireless controllers, but I am sure 360 would have gotten to that stage eventually, I think that the only major factors that PS3 brought to the table were;
The alternative to X360, direct competition, brought about competition between companies - price cuts earlier than anticipated and all those little things that make the consoles stand out to the consumer.
Extensive exclusive games library.
Wireless controllers
AND BluRay , although it's not spread on the other consoles but it's a good method of storage and allows developers to do much, at least on PS3 which is the only one that uses the format, I would have liked to see similar format on X360.
All in All, seeing as it was the last console released I don't think it had such a large influence in terms of hardware etc since those can't be altered.