You can try something like Steinberg's Magneto. Not a bad little plugin for warming up digital tracks. Certainly not a cure all either.
One of the problems with digital synth's is that they are a "picture" of a sound. Analog synths have actually electronics that produce the waveform. It is a very big difference in sound.
There are some effects that just don't sound as good digitally. Chorus, Flanger, Phaser, and Tremelo just don't sound that good on digital boxes compared to their analog counterparts.
A band I work with from time to time really likes to put some wacky effects on unsuspecting instruments sometimes. Like distortion/flanger/delay on a Saxaphone solo.

The keyboard player has a whole slew of really neat pedal effects. I always ask him to bring them along when we mix because these analog pedals produce effects I could NEVER get from ANY digital box!
It comes down to price vs performance/quality. Indeed, it is neat that so much is available these days for pretty cheap in the digital market, but the cost vs quality department is STILL a major factor. A $200 software program just isn't going to deliver the sonics of a $5000 hardware piece. Just not possible yet.
"Emulation" is just not quite "the same exact thing", and sometimes, not very close to the real thing. The quality of the software code writing is a major factor. More times than not, software code is intentionally written for "perfomance at this price" rather than "high quality". Often, they figure you won't hear enough of a difference to worry about the much more sonics of a plugin compared to a hardware device to justify the big price difference. YOU think with a little "tweaking", you can make it "the same" (or at least, that is what the software company is hoping you will think...they KNOW you can't, but they need to sell a product here....

)
I am sort of negotiating with a band right now about mixing a CD for them. One of the guitar players really wants to mix it himself. He also tracked it all. The other guitar player is a client I did a pretty good job of mixing a CD for him years ago. Neither of them are liking what they are hearing right now on their product. Dood A (the guy that tracked and wants to mix it) thinks he just needs to retrack a few things. Dood B (my old client) suspects THAT is the problem, Dood A is too close to the production.
Anyway, they start telling me that the whole thing is being done in ProTools.

It was at that point that I stopped talking about anything other than listening to the tracks somewhere else. A lot of the problems with their production they are articulating to me are problems I have heard with EVERY PT mixed thing I have heard. They are trying to get a sound that PT won't deliver, they just don't know it yet. I basically told them it wouldn 't be worth it to hire me to mix if mixing in PT was the only option. My experiences with mixing in PT have not left a good taste in my mouth, nor much confidence that I can deliver the sonics in a mix that I hear in my head. I am realistic about this. I know the limitations of PT in a mixing environment. I KNOW that to "step up" the quality of the mixing on this project, it NEEDS to get out of PT and on to something else. The "ProTools sound" is not flattering what their music needs. No matter how much any of them wish that DSP package can deliver the "real thing", it WON'T.
Anyway, just some ramblings.
Ed