I don't post any graphics, so I doubt that my posts are slowing down anybody's internet experience. As far as seeing more of what matters, again, a single line within a forum page doesn't take long to skip, nor does clicking over to a new page--which is rarely necessary given the speed at which the Wishlist developes. When responding to another's thread, I rarely make nonesense posts--at least not beyond the level of absurdity set by the initial post. Regardless, much like I flip the radio station when I hear a couple notes of a song I can't stand, so too can you when you read the name of a poster you find disagreeable. Having a machine do your thinking for you always leaves the chance that you might overlook a piece of relevant information from an unlikely source. At least that's my thinking on this matter, and the reason I wouldn't use the machine.
As far as my concern, no, not particularly. Amazed may be more like it, as the staunchest critics of my posts tend to do anything they can BUT ignore. But this is nothing new... This system had an ignore feature earlier in its history and this didn't stop people that supposedly hated each other from being each other's most active thread participants. My bet is that even with an ignore feature, many will still not be able to help themselves and periodically check in to see whether there's an opportunity to air grievances.
Like I said before, an ignore feature would largely serve the purpose that your brain should. If you require that assistence, you should definitely have it. You can also leave in your sig line a list of people you've set to ignore--as some do--just to reinforce the degree to which you've let somebody get to you.