At higher level for nearly the same resource you can use aid to the same effect as healing word.
Except it doesn't stack, has half the range, requires an action, uses up higher level spell slots, and isn't available to as many classes. But yes, aid + cure wounds is a much more sensible package than just cure wounds.
How can terrain and enemies cause AoOs for your cleric? Doesn't the cleric set up with your melees to deliver other touch spells that might be needed?
_You_ just covered how your cleric stays back around a corner to avoid having his concentration broken! Nevermind that _anyone_ grouping up is just going to get tagged by AE and lose their concentration. That last battle included a dragon with 60-ft cones that it used on both of its turns, melee guys who literally dropped onto us from nowhere, as well as attacking from a more expected/scouted flank, along with a necklace of missiles hurling NPC (so, a fireball every turn). The entire ground was difficult terrain so only the two flyers I was maintaining and the melee who had boots to ignore the difficult terrain weren't impeded.
At lower level, we still had dragons, flameskulls, and lightning-breathing drakes, so things really haven't changed much from that angle on the AE front. On the supporting melee front, corridor chokepoints don't tend to work; goblins, toads, spiders, fliers, lots of things just traipse on through to the backline, nevermind that any engagement in such a setup will almost always call for reinforcements from another angle if they're available.
It's also often important to maintain multiple tactical points, for example holding off reinforcements at one point, rescuing an injured NPC at another, and dealing with the primary target at a 3rd. If the cleric is doing any of those, their ability to move to someone doing another is compromised, as well it should. This is sufficiently true that in some cases the fighter might be more than a full move away from the cleric, nevermind in a situation that might provoke attacks to get to.
Like I said, pretty different game from yours.
You're fighting a dragon. You get a character back up with healing word. Dragon claw attack hits, character drops. Second claw attack hits. Character misses two death saves automatically due to crit.
So use cure wounds instead. Odds are high that the character still drops in the same number of hits, because the difference cured is small. Further, you're now more grouped up for the dragon's wing buffets and breath weapon, which mean that your healing gap is even worse.
The real question, though, is why the dragon gets another turn. It can't drop anyone in the first turn when it shows up or you're setting up, it might drop someone in the second if it gets one, it's dead before it gets a 3rd.
If your DM doesn't go for the kill after you fall, I can see you choosing healing word.
That theory does not apply to the games I know. There are uses for cure wounds, and I would take it - AFTER healing word. There's no question there are situations in which cure wounds is better than healing word. Like I said earlier, about 1/6th of the time.
And the better option than both of those is for the enemies to never get another turn, instead. But, sometimes you got to heal, it does happen.
When fighting legendary creatures, even their lair actions can be used to finish someone in that state. We lost a few party members to the lair actions after they had fallen.
Yep, we were definitely worried when he dropped both our tank and our "healer" (the imp) in the same round, but thankfully he had used all 3 upgraded wing buffets (now that I look at it, he was doing more than the standard damage since it's impossible to roll 19 on 2d6+6 and he did 50-something over the 3 times he did it, doing it as a single action not a double action, _and_ not allowing a save to negate the damage like usual. wow). He was also trying to stay flying out of range of melee attacks while using his breath weapon every round, which is solid given how much damage we do with melee.
So, yeah, he was trying to present a real upscaled challenge, not just playing tag.