Universal smd pad size, bad idea?
If somebody might want to assemble this board with automated equipment (pick and place), you don't want to do this. When you place a small part on pads that are too big for it, the excess solder will move the part around and cause defects, such as "tombstones".

If your circuits will only be assembled by hand-soldering, its certainly possible to make pads that will fit more than one size part. For example, a footprint that can fit 0402 or 0603, or a footprint that can fit 0603 or 0805.  But trying to span the broad range from 0402 up to tantalum capacitors is going to make it more difficult to solder your board. 

It would probably be better, unless you need to work with very high frequencies, to just design with maybe 0805 footprints. Hand-soldering you could probably put anything from 0603's to 1012's and A or B size on an 0805 footprint. And it's possible to get even very low valued capacitors in larger footprints, whereas if you choose a smaller footprint there will be some maximum C value available in that size.