I wouldn't say it's boring. Yes it may take time to get from A to B - but that's part of the realism. This is the West. And a horse is not a Ferrari. In real life it took them days to get from one town to the next, not 30 minutes.
Also, Rochstar has tried to lively up the routine - when you suddenly get eaten by a mountain lion, or some thugs try to mug you.
Of course I can only tell first impressions of the game, but for a ego shooter its refreshingly different to many other.
And the look of the nature and all that is really cool, combined with the ability to go where ever you want (more or less).