I will have a look into that way, not considered some of the techniques before, especially on the toms... Here is what I do to mix drums without replacing:
Group all drum tracks to a buss. No need for EQ or compression on the buss yet, I usually do it last. Then I check for phase issues before I start on the processing.
KICK: There are a few things here, usually I gate first, then use an EQ to cut any muck out of the kick (usually resides around 300-400Hz for the most part) and then find the point where the snap is on the sound and boost it with a fairly narrow Q (but not so much that it resonates and gives a weird sound, and not too much) Then I use a Highpass filter below 40Hz to get rid of the extra rumble that will clutter the low end later. If the kick has no real thud or if the low end has been poorly captured, I use a signal generator to make a sine wave at 50Hz, and then use a sidechain gate on it so that the sound only plays when the kick hits. I then use some compression to glue the EQ I used, depending on the style I might use very different compression but I always leave between 30-50ms attack time to let some or all of the transient through without it being squashed down, which leaves us with a nice and punchy kick.
SNARE: It depends on how many mics are used. If say only one SM57
is used, I generally gate the snare first, then use another highpass filter to roll off everything below 80Hz. If the snare sounds too thuddy I cut around the 350Hz area (depends on your snare sound) and boost a bit at 4-5kHz for the sizzle. If after the boost it sounds a bit papery, I add back some of the cut at 350Hz to thicken it up. Then I compress to taste. Try different compressors on the snare, it can give vastly different results. My go-to compressor plugins for snare are Voxengo's Crunchessor, Waves' RComp and Stillwell's Rocket. Crunchessor gives a really fat sound when driven, Rocket gives a really retro, almost distorted sound, and RComp gives a smooth and rich sound. Then I usually create a reverb track and send the snare sound to it to add the reverb to it. I am a fan of the gated reverb, used a lot in the 80's. Sounds great!
TOMS: The toms are probably one of the harder sounds to get right. Generally I gate, then set the sidechain filter on the resonant frequencies. Next I EQ to remove the clutter (depends which tom you are doing it on, experiment with the EQ to find the best place to cut) then I use a highpass filter below the resonant frequency and a lowpass filter above the frequencies where the attack is at. That way I can clear out the high end for cymbals and such. Occasionally I add some subtle distortion to the tom tracks (one with a wet-dry control) so that I can really bring out the resonances but still leave it punchy. But too much distortion is a bad thing so you have to go carefully. Changing where it is in the signal path also leads to very different results.
OVERHEADS: If the overheads sound good as they are, I roll off below 40-70Hz and then use a very light compression (usually ratio of about 1.2-1.5) and then I can set a lower threshold to give the overheads a really smooth and tight sound. If the overheads are not quite right, I usually just use shelving EQ to bring out the parts of the overheads that I feel are missing or lacking, and then go from the start with the HPF and compression. Usually, subtlety is the trick with overheads as you can get a very musical sounding overhead track without it sounding overcompressed, and the peaks will be under control.
ROOM: If there is no room mics, I duplicate my overhead tracks and then I put them to a separate group (which then runs to the drum buss). On this group, I use a transient enhancer, but I de-emphasise the transients and bring out the release time of the group. This gives more of a washy sound to the group and makes it sound further away from you. Then if necessary I use reverb as an insert on this channel (very short reverb time, use the filters to taste and cut out the low low end, no pre-delay (you will see why in a minute)) and this really adds the roomy touch when you get the wet-dry balance right. Then I offset these tracks by a few ms (this emulates the sound hitting the further mics at a later time as sound does not reach the room mics at the same point which it meets the overheads, of course with no room mics we have no extra mics so we have to use this to emulate the situation) Then I set the levels on the entire kit and mix the 'room mics' in to the kit sound. If you want to go crazy, you can also try using a very driven compressor after all of this to really make the room pump.
If there is already room mics, I usually roll off all below 70Hz to get rid of the boominess that may have been picked up, and then I may do a variety of things. Again I am a fan of the pumping room sound so I will try the driven compressor first of all to see what effect it has.
WHOLE KIT: Now we have got everything sorted out I usually just need to add a bit of compression to the group to glue the drums together. This time however I use the compressor differently. First, I set a very HIGH ratio (say 12:1, no I am not nuts, keep reading!) with attack and release at 1ms and 5ms respectively. I then set the threshold to the point where I can see that the compressor is squashing down every hit, but is fully released before the next hit comes in. Next, I adjust the attack time to get the punch I want, and then adjust the release time to get the smoothness I want. After this i turn the ratio back down to a point where the compressor is glueing everything together, but not overcompressing the kit and killing off the dynamics.
This will leave you with a very punchy sounding kit, with a smooth high end. Great for a lot of mixing styles, I have used it from some light pop mixes to heavy metal! I hope it helps out some beginners! Remember, everyone has their own way of doing things so a lot of people may think the way I do it is a load of poo and the rest may agree with my method. Try it and see