As stated before: Maemo is dicontinued and it thus doesn't make much sense to invest futher time into gpxview.
Regarding your questions: 1) Wherigos are not documented nor did they really take off. To support wherigos one would have to reverese-engeneer everything. On the other hand that's not worth the effort given the fact the basically noone uses wherigo anymore 2) Alternate coordinate systems are rarely used in geocaching, so it would confuse more people than it would help. Plus this is also a significant effort.
So no, none of this is considered for implementation in gpxview