1. The materia melding system is fine. Tipping the melder is optional in many cases, and while you may have come across some bad crafters who overcharge, many of us are more than happy to provide melding services free of charge since it costs us nothing but time.
2. Glamors are for any level, but all the 'good' stuff is level 50. The whole concept is stupid, in my opinion. they've made the recipes incredibly difficult either to craft, or get the ingredients for. They should've been more sympathetic to the players, and at least offered some other unique items at lower craft levels and lower item rarity. Sadly, the way things are going, everything is going to be a 3-star synthesis requiring godly rare items, and yes... I agree, it's retarded.
3. Shards. Praise be to Hydaelyn for giving us wards to enhance the yield, but a pox on the idiot who decided that they should only increase yield by 2 at level 50. 12 shards per node, 18 if you've got 700 GP and a +1 node. I use that up in about 2 syntheses. This needs some SERIOUS revision, but SE have basically ignored everything about gatherers and crafters. They're too focused on the 'what next' not on what came before. Don't expect them to revisit shard drops any time soon.
4. Dungeon roulette is fine. I get that its frustrating to be thrown into a Tam Tara at level 46, but it's designed to help the lower players get teammates for dungeons they need to do, not to help high levels level up. You get a daily bonus of XP which is very sizeable irrespective of what level you end up at, and a further XP bonus based on your level compared to the dungeon. It's as fair a system as it can be while still serving its original purpose.
5. Guildhest was a good idea... then it became incredibly tedious and uninteresting. The problem is there's very little variation, and no new guildhests have been added since the game released. It could do with a bit of reworking.
6. Well, FFXI had companions you could level up and equip so I wouldn't totally dismiss the idea. Though, don't expect AI on the level of a player. Game mobs are notoriously stupid, so it stands to reason that retainers in the field won't be much to celebrate either.