Agree with the reply to this post that RPG spamming would go through the roof.
I actually like that only the support class can resupply and I have taken on that role out of the squad that I have been playing with.
People that play the support role and don't revive and don't resupply are missing out on crazy amounts of points and XP so more fool them. Clever use of the support role will ensure you come very high up the leaderboard in most games.
I do agree with you that having classes being able to use all weapons is terrible as you do get self healing and self-supplying snipers. However there is a restricted class mode for conquest available in the beta and this is a much better throwback to the old battlefield games and plays much better. It's a shame that they didn't just force this into all game modes.
Perhaps try and connect with some players that are good support players and try to get them on your friends list? There must be some decent support people out there who aren't part of a clan.