An advantage of a simplified system is that it is easier for a reader to stat up their own vehicles. You might not provide me with stats for a Ratel, for example, but it is far easier to assign it stats myself if it is covered by a few simple, plain English descriptors and maybe a few unique traits (something along the lines of D&D 3.5ed feats, just for vehicles. For example: bogs down easily, open topped, mine-protected, etc).
The reality is you are unlikely to be able to stat up every vehicle there is (a Rhodesian crocodile? The A-Teams van?) if your rules cover an extended period of time, so the ease with which somebody can add in stats for their own vehicles should be considered.
Those are brave men knocking at our door. Let's go kill them!