Exhaustion is Convoluted and Stupid

I said it, you heard me. Here’s a replacement that requires no memorization and isn’t friggin’ terrible to use:
Players Handbook p 291: Appendix A, Exhaustion Sidebar: Replace entirely with:

Some special abilities and environmental hazards, such as starvation, lack of sleep, near death experiences, and the long-term effects of freezing or scorching temperatures, can lead to a special condition called Exhaustion. If an already exhausted creature suffers another or repeated effects that cause exhaustion, its current level of exhaustion increases by the amount specified in the effect's description. An effect that removes exhaustion reduces its level as specified in the effect's description.
A creature suffers a 1 point penalty to Ability Checks, Armor Class, Attack Rolls, Concentration Checks, Damage Rolls, and Saving Throws (including Death Saving Throws) per level of exhaustion they have currently accumulated. Additionally, when an exhausted creature uses a spell or ability which causes another creature to perform a saving throw, that saving throw has its DC reduced by one per level of exhaustion experienced by the exhausted character.
A creature gains a level of exhaustion when a spell or effect states such, or at the DM’s discretion, such as when enduring extreme environmental conditions or extended strenuous activity. A cumulative level of exhaustion should generally be applied to a character for every 24 hours they go without sleep, every 24 hours without water, and every 48 hours without food.
A creature gains a level of exhaustion every time they fall unconscious due to being reduced to zero hit points by damage.
If a character accumulates a level of exhaustion equal to or greater than their constitution score, they die.
Finishing a long rest reduces a creature's exhaustion level by 2, provided the creature has also ingested some food and drink. Also, being raised from the dead reduces a creature's exhaustion level by 1.

Old and busted: RAW Exhaustion.
New hotness: One level of exhaustion: one point penalty on everything meaningful. Two levels? -2 all around. Done. Easy. No insta-death at 6 levels anymore, and the maximum limit is effectively one’s Con score… but if you gain a half dozen point penalty from, say, dropping to zero HP over and over, not sleeping, or starving, etc. That huge penalty on just about everything you do? Best get some rest, quick, or the cold embrace ain’t far off… This version is much more granular, still meaningful, but not as sharp a decline, and much easier to use in moderation than the original, which was often a death sentence at only a level or two. Furthermore it will come into play more often, increase the value of healing, and make dropping to zero HP far less trivial than in the current iteration of the game, a simple solution to the problematic scenario that it is often more efficient for a party to let a character drop unconscious at zero HP then heal them minimally before their next turn, allowing them to act at full effectiveness as if nothing bad had happened, rather than have any impetus to keep them from hitting zero at all. The tiiiimes they are a’changin’.