Ive got some guesses as to why they did some of the things that Inverse mentioned....
There seems to be a definite aim for Sega/Relic to make a game that is different from vCoh. Im sure that this is driven (understandably) by upper mngmt who are concerned more with getting sales than pleasing the somewhat small community that desire to play the game for the next 5+ years. Im thinking that in general these "thoughts" about making the game different trickles from them to the upper development team and they are left trying to come up with mechanics to replace/change/add into the game to ensure that it doesn't come off as just vCoh 1.5....
This undoubtedly leads to design discussions and ideas of how to "change" and in their minds "improve" the game. One of these must of been the idea to improve the realism. And out of this thought maybe came the idea to remove/reduce the tracers/smoke and size of bullets/nades etc because these items don't look realistic on the battlefield (for lame example: when zoomed in).
This probably ran through design and when it was implemented and they "tested" it they thought, wow, this looks so much more realistic. The issue comes from the fact that developers (especially upper mngmt) don't play the game (even if they say they do). So, these items make it into the build and seem like a great idea for a couple testers who played a couple games against the computer zoomed in to see how it looked (and hardly a thought was put into whether or not this breaks the game for those who desire to play it competitively/ladder). Thankfully there is a beta, but if the changes implemented are there because of "requirements" to make the game different im not sure how much of it will be changed. Lets hope they give some thought to those of us who want the game to be competitive (especially since we'll be the ones playing the game years down the road).
Of course these are all just my opinion, and we know what those are like.....