Not sure where you got that from... I got the W (2009-) version, the gears are reasonably evenly spaced, and is not a nuisance to use at all. Mine came with a simple barend style thumb control lever, very simple to use. The only small criticism I have is that the lowest gear does not feel smooth, there is a small amount of brrrrr feeling as the little gears mesh. The other gears are not like that. Mine has the Brompton spline, so the bikes are 10-speed.

I have found that works very well indeed, mostly the standard Brompton shifter is used to switch between 2 gears, when tackling steep uphills, the additional 5-speed lower gears are used, or when going fast downhill, the highest 5-speed gear is used. For most normal riding, the 2 extreme gears are never selected. My wife has not ever mentioned that she finds the combined gear selection complex.

Perhaps yours is an older version?