If they should get together I don't think it has to change the dynamics of the show. Rather it just might give them more opportunities to play off the differences between the two of them. The show hasn't been based on Leonard trying to get Penny outside of the underlining current.
For me the show has evolved around the social ineptness of our lovable nerds. With Penny becoming closer to them it opens up all kinds of wonderful opportunities for new ineptness! I'd really like to see Wolowitz met a few of Penny's promised friends... right there could be a season or two.
I just hope they don't manipulate the relationship too much so it begins to look like Men In Trees
. Where they get together and break up ten times an episode.Two and a Half Men
(another Chuck Lorre series) manages to keep Charlie and Rose fresh after five or so seasons so I tend to think it's not what happens rather it's how it happens.