See, I'm a veteran D&D player, so I build my own campaigns... and monsters, I guess, so some of these problems I simply sidestep
By and large, though, 5e feels
a lot more balanced out of the box than anything before 4e, which was
too balanced. It's basically a redo of 3.5, but they kept the awesome additions of 4e (like at will spells) and added attunement (for Magic items) and concentration (for powerful spell effects that last a while), which fixes a lot of the problems 3.5 had. I mean, if you think that Wizards are overpowered from the mid game on in 5e, you haven't played 3.5! Melee characters are way more useful in the mid to late game than they were in 3.5.
In the end, the 5e rules are mostly about combat (as D&D has always been). The idea is that roleplaying doesn't need many rules, and looking at my own D&D campaigns this is true. I've had an awesome session last Monday, and it didn't feature a single combat!
If you do want to change things though, I've found 5e is a great system for house rules. I do agree 6-8 combats in a single day every time feels like a slog, and while I've not personally had any problems with running less combats in a day, one of my groups recently switched to a system of... delayed long rests? Basically, we do the 6-8 combats recommended for a single day, but we don't do them in a single day. Spells can be used out of combat, and depending on the situation this might or might not cost you a spell slot. After all, if you are spending a few days in between combats you could easily cast that raise dead under the normal rules
It works pretty well, no forced combats, you are exhausting your resources, melee characters are more important because they are such a dependable source of damage, unlike spellcasters which are much more burst-oriented.
The great thing about that healing word being a bonus action is that healers can actually do something else besides being a medic all of the time, but if you want to slightly discourage people from dropping to 0 on purpose so healing has full effect (and I've been there), you could introduce a house rule that limits a character in some way when they are revived. Note that you already drop prone when you fall unconscious, so the first thing a character typically has to do is spend half their movement speed to stand up. Maybe you can only take basic actions as you reorient yourself (cantrips or a weapon attack, no bonus action)? I've tried handing out an exhaustion level for dropping to 0 hit points, but the lasting negative effects mean you're more likely to drop again, so you get a negative feedback loop, plus exhaustion typically hits melee characters way harder than spellcasters, and melee characters are more likely to drop in the first place because they're in the frontline. So, that house rule wasn't fun for the players. A small penalty like the one above might do the trick though!
For DM's, I highly encourage watching this video:
. This is a great way to make your monsters more memorable!
Another great resource is this one:
https://theangrygm.com/series/5e-boss-fight/
