Personally I think the problem is not voice or not voice chat or chat, lobby or not lobby, all of this don't do difference on the main problem: find players for play. The game is particular, is not a TW where you can enter and play, you must organize the match much before , also with a potential lobby. If some of you played a Scourge of war (a game with similar target of LG) know that the game lobby don't resolved the problem of organize a match (also because of the connection problems which permit only to some players to host).
So the solutions are two: organized leagues, but this is valid only for players who want partecipate, or a system, at example on this website, similar a prenotation board where players can indicate the day\s-hours where they are free for play a free matchs (with settings and type of game), other players could read this and prenote their place for the match if they are also free that day\hour: so all people will know days before when and with who they will play, with what map and army, and no people will lost time waiting all the evening for players in lobby or in xfire. After you can use xfire, tunngle, steam, it doesn't matter (the system are not mutually exclusives, xfire work also with tunngle open).
I also suggest to create a better interface for PBEM challanges: the old Combat Mission is still played after 10 years because of PBEM system. A scoreboard will be also a big incentive for the h2h games.