I don't think it will affect resource management *at all*
Lets assume a typical party of four 5th level iconic PCs. They go against a low level challenge (8 orcs). The orcs might get some blows in, but ultimately the group takes only minor damage.
Under the current system, the cleric either uses his CLW spells OR a wand, scroll or potion to patch up, or the PCs sit with 80-90% of their hp (and I will eat my hat if you know a PC who goes into the next room with less than 80% hp if healing is available). Now, the PCs get a couple touches and boom, they are 100% healed.
Now, they face a terrible foe, like a giant. Something that can deal horrible damage. Our fighter (who has 40 hp) takes 22 from a giant's swing. He's down to 18 hp. The cleric now has a choice: Touch for 9 hp (total 27), or use the reserve spell for 3d8+5 hp (ave 18, or 36 hp). The choice is even HARDER if that was a crit and the fighter is at 8 hp (17 or 26?).
I don't know if anyone else does it this way, but when the cleric is nearly out of healing, we STOP. We camp in the woods and heal up. It costs us two days rations and a couple checks on the wandering monster table, but its better than going against that giant with only 80% of our hp and/or 50% of our spells. It will increase the speed of play, lead to less time spent camping (aka wasting time) and allow for more interesting storytelling. Thats OK by me.
Again, I'll wait for the full text (C'mon WotC, let that text slip) but I like the idea of being able to heal some between battles without draining the cleric of his big heals.