Can I skip the downloading and patching phase that happens before the game launches?
Solution 1:
In order to play the game offline, you need to log on at least once. In order to log on, you need to get that first patch. So unfortunately, no I don't think you can play without it. If you want to play online (which includes the single-player campaign if you want achievements etc.) you must always be fully up-to-date with patches, similar to World of Warcraft an other online games.
The patcher itself should have links to technical support sites in case you are having difficulties. You may need to adjust your router, firewall, or peer transfer settings.