I think you may find a few 20mm stuff to after the scale creep to be close to 25-26, these will look fine next to BFEvo.
But on why did they choose to do a scale game?
1. It looks better, you can look at a transport and say it would be a tight fit, but the army never went for good seats.
Take a Rhino is there a shrink ray on the door?
Why do you think so many compines say 28mm but the figs are 30, 32 even normal men who crest 33mm?
Most us 1/48 or even 1/35 vechicles to make them look right with the figs.
So if you do not use thier figs yours will look small, and most men get worried if thier fig is small.
2 Yes, Mongoose would like you to buy thier figs, they do not make alot of money posting the basic rules for free, (you would get fired for suggestting to place free rules for your next big game at many places)
and then charging only 25USD for the Advanced Book.
The figure sales are how Mini based compaines make money.
Now lets look these true 28s, these "small" as you call them figs, will allow a lot more moving and gaming. and yes 1/64 is a huge scale again used to be S in trains and died, but came back in diecast and more than a few kits.
For clutter I was able to get 10 1/64 cars for 10 USD, I got a 18 Wheeler, and 2 Panel vans for another 12.
So, in closing.
The rules play well, the vechicles and infantry look to be scaled together, yes tanks are really that small, and Mongoose has 3-6 lots dropping a month.
Give it a try, for 2 units of BFEvo will run less than 1 boss from other lines.
If your not going to give it a try, I think it is too late to get Mongoose to change scales.
Who knows perhaps this might get other compaines to look at thier lines and say, if we put them in scale "they woul look better"
Good Gaming
Hope you find what your looking for,
Lee