While the current implementation of bloom makes a lot of things much prettier (explosions, objects in front of large stars, etc), it also has some issues - from what I understand, the implementation hasn't changed much in 9 years, except to add the High Quality option which makes it a little better, but it can still look fairly ugly in many circumstances.
One issue is that, even with High Quality enabled, there is noticeable flickering of bloomed objects in many situations. Another issue is that the bloom can look very "boxy" if a small (in screen-space) object is being bloomed. Here are some example screenshots (all taken with High Quality bloom enabled):





Somewhat relevant: an efficient multi-pass gaussian blur implementation in GLSL: http://rastergrid.com/blog/2010/09/efficient-gaussian-blur-with-linear-sampling/

+1

As a photographer (and NOT a private military goon, as Genka seems to believe.) I can attest that has never made any thing look worse when used correctly.

+1, as option
+2 to use improved GLSL tool

On my netbook, AMD Vision (C-60+Radeon HD 6290), using full scene glow is much more impacting than 2xAA... like 4xAA is also lighter, reducing to 35 FPS, while no AA buut HQ glow results in 20 FPS...

Maybe a radeon HW limitaion. I used both Fedora-provide and latest AMD-provided, same results.
(Both are faster than Win7 on same HW)

Full scene glow is very fillrate intensive; I believe it's a multipass render-to-texture effect. There are other ways of going about it, but some of them are exclusive to very "recent" hardware. The method we used had the broadest compatibility.

But, I'm always in favor of improving graphics if/when we can. I'll run it by Ray. We'll be doing some graphical and engine updates a little later in the year anyhow, so there might be some value in taking a look at it then.