I think that Europe needs to have a central " Eurozone " control with less frequency changes. The current 833.3 Khz VHF frequencies in use are prone to mistuning and " miscopying " by pilots whose first language is not English; add in the various German, French, Italian and Eastern European accents...we have a recipe for disaster. Do like what we have in Central America........cenamer control, etc. It isn't so difficult in a radar environment to have a South/ North/East/West/Central Euro control with less frequency changes. Only snag, some job losses and fewer ATCO bosses to build their own little fiefdoms
The number of ATC sectors and frequency changes in Europe has to do with the pure volume of traffic. Even ignoring state borders (there IS an Eurocontrol) there would not be less frequency changes. Traffic levels in Central America cannot be compared with those in Europe. In Central Europe areas even upper air space is split vertically split into up to 4 sectors to cope with demand (see FFM or Zürich). The observation that 8.33 MHz freqs can be mistuned is right as about 20% (own, non-representative count) of all frequency change instructions crerate a reconfirmation request by the pilot. Has nothing to do with the naitve language and accents, but 6 numbers is much to remember. But even with a mistuned freq one can return to the previous freq if only diligent tuning procedures are used.