Contagion never did what you thought it did. It is fine as written.
The spell as written in the PHB disagrees with you. If your point is that the spell was intended to be a non combat spell, then fair enough, but it is not written that way. The spell uses the word
afflict for the immediate effect upon a melee spell attack (not
infect). When one succeeds on three saves they 'recover' from the disease, if they fail three saves the disease's effects last for the 'duration' (as opposed to not lasting the duration?). Notice that it is not: 'the disease takes effect and lasts the duration'. If the devs really thought that this meant what they now say it does, they need to revisit English class.
So, that is fine if we want it to be a non combat, flavor spell, though I would point out that the effects listed for each disease are specifically combat related. Furthermore, it is unique in that most multiple save spells are either a duration meter (
Hold Person and many others) to end effects already in place, or have progressively worse effects upon a failed save (
Flesh To Stone), and that purely non-combat spells that have detrimental effects on the target tend to have a longer casting time (
Geas,
Imprisonment). But to have to jump through the hoops of a melee spell attack (which usually implies combat, or at least rolling for initiative), plus the whole three failed saves seems a bit much, even for an out of combat flavor spell, particularly for a fifth level spell slot.
Now, I will concede that this may be one of the spells that is best used against the PCs, even relatively low level PCs. You could probably safely use this against first level PCs for flavor/plot reasons. Even if they fail all three saves, it just means that they have to quest for someone with a
Lesser Restoration, if indeed they don't already have someone capable of casting it in the party. Though why an NPC BBE would waste a 5th level slot on this remains an exercise for the DM. I can think of several plot, flavor reasons. There is also the idea of using it as a monster ability: an add on to the bite/claw/slam attack of the Death Hound/Dread Wraith/Hel lizard.
As for
Barkskin, I agree that there is nothing 'broken' about the spell mechanically, it is just written in a weird way. I think I might just call it 'Warding of the Trees' or 'Wild Warding' and keep the effects the same.
Jump - But I want the sound effect dagnabit! Seriously, I guess my main problem is that it is just a little to fiddly for it to be worth it. I want to be able to just do some cool jumping (within reason) without having to go through all the jumping rules.
Blade Ward - I guess I agree. I was on the fence about this one and had never seen anyone take it.
True Strike - I still think it needs help.
