Perhaps they have been gone, but in 3.94a8 there is a preset called --preset dm-medium and a preset named --preset medium. Both have very different results both lower bitrate, but --preset dm-medium seems to be preset standard with a lowpass, while preset dm-medium has a higher bitrate preset medium does seem to include more high freqs. For example I will post a quick test I made earlier this week.
Recommended presets Enc.Time Bitrate Filesize
--preset insane 1:40 320 9,342,756
--alt-preset extreme -Z 1 2:36 254 7,430,534
--alt-preset extreme 5:30 254 7,426,366
--preset fast extreme 1:48 265 7,757,198
--alt preset extreme -Y 6:44 230 6,733,692
--preset fast extreme -Y 1:36 208 6,078,302
--alt-preset standard -Z 1 4:38 194 5,687,266
--alt preset standard 3:17 199 5,820,920
--preset fast standard 1:28 207 6,063,536
--alt-preset standard -Y 3:48 181 5,305,498
--preset fast standard -Y 1:26 189 5,521,392
--r3mix 1:48 184 5,391,440
--preset dm-medium 3:53 181 5,305,498
--preset portable 3:15 172 5,047,162
--preset medium 3:27 164 4,795,544
--preset dm-radio 3:18 159 4,662,666
--alt preset 128 2:15 124 3,623,187
--alt preset cbr 128 2:17 128 3,740,315
--preset radio 1:51 107 3,130,453
--preset fast medium 1:52 177 5,172,542
--preset fast dm-radio 2:59 181 5,308,002
--preset fast portable 3:16 173 5,049,666
--preset fast dm-medium 3:31 181 5,308,002
The test was more extensive than this including many more lines and a few other things besides bitrate but I posted this earlier in a testing thread and it still seems sufficent now.