Just some things I disagree with Leo about.
Personally I loathe the idea of "mook" enemy types that have only 1 Hit Point but look exactly like regular monsters. Like, wtf, is this a race of Pinata Orcs who faint at the sight of blood?
The minion system was created because lesser enemies in 4e and especially 3.5 are rather pathetic when against more powerful PCs. Whenever you need a bunch of fodder enemies to protect a boss there is basically nothing you can do because anything that are a threat to the PCs cannot be in sizable numbers.
Minions are a way to rectify that problem by allowing easily disposable enemies that have a good chance to hit you, resist effects, and deal existent damage.
In other words it is a well intentioned system but one that didn't quite work.
Though I'd take the Minion system over sending flocks of level 1 enemies.
I think it's weird that a Bard can hurt someone by singing at them. Sure, in Final Fantasy you could spew musical notes out your lute and it's fine, but I didn't think D&D was supposed to be like that
Dungeons and dragons had that for a while actually. Mind you they were essentially "song spells" (spells where the verbal component was singing or playing an instrument) but whatever.
Heck "Somatic Component" is left intentionally vague. There literally could be a wizard out there who casts fireball by dancing the flamenco while singing a passionate love song and it wouldn't even be stretching the rules.
Similarly, a leader can shout at someone and heal them?
HP, in 4e, represents the ability of someone to stay in the fight. Dungeons and dragons already keeps hp in a sort of nebulous zone of being both plot armor and being constitution.
The Leader's shout inspires the person to fight on. Thus their "healing" represents a sort of second wind.
that the game system requires PCs get magic items because otherwise they'll be underpowered and the rules break
That has always been in dungeons and dragons as well. Though it is the equivilant of a western setting and not having a gun. Dungeons and dragons is a world of monsters and magic and if you do not use the tools of the setting, then you forfeit the ability to survive in the setting.
They went template-crazy, like the joke about the Frenzied Arcane Spectral Astral Phase Infernal Giant Half-Dragon Half-Spider. It's like, can't we just have an Orc? I think they did this to boost sales of miniatures and to create intellectual property (proof one way or the other would be lovely to see).
First of all that is 3.5 as 4e almost never used templates. Second of all templates are simply alterations one can make to a monster, creature, or being.
No one went template crazy. It is up to the players and DM whether to use them and most campaigns and stories do not use templates extensively unless it is a gimmick dungeon (such as a clockwork mansion where all the monsters are mechanical mockeries of the real deal) or they are undead.
At its best the template either feels like a type of monster in it of itself (Like Zombies and Skeletons who are template creatures), give an interesting twist on an enemy of NPC, or they flesh out the current setting more. Having many templates to use is no more "overboard" then having a lot of monsters "Why use a Raksha? Can't we just have an Orc?".