There's only a few problems I'll see with that allowance of cross-platform multi-player between PC to PS3.
- The allowed script changes for your configuration will be downsized.
- Modifications themselves may cease to exist, or just not be nearly as changeable.
- The usual FPS port issue that the majority of games within the recent years have suffered from, being that the PC version is just a console port.
- General update/support will be more functioned towards console users.
- Matchmaking, enough said.
- Downloadable content, such as maps which have always been free for CS:S will more than likely be additional costs.
Then again, this is just me nitpicking at tiny things that bugged me a lot when COD:WaW and MW2 came around and killed off my interest/hope that PC FPS gaming would still be a decent, advancing, competitive atmosphere.
The higher graphics quality is the only thing appealing with this, as CSS was slightly dated.
Besides that it seems like the same game, better graphics engine (which hopefully doesn't break the gameplay) and a stupid molotov addition.