Changing the move rates would be pretty easy, but adapting the attack rates to follow suit sounds like it could get bearish - unless they are both fundamentally based on ‘turns’ and not time?
One of the biggest problems I always run into in game design for combat systems is the rate of melee attacks vs real movement. For example, a trained sword-fighter COULD attack once a second, or even faster - for a very short period of time, but if they tried to actually do that for more than a few seconds even the most well conditioned would be out of breath, and in less than a minute of such an unrelenting pace, they’d literally collapse.
Most of the time people spend in real melee combat is spent doing more or less nothing - looking for openings or targets, trying to regain/keep your balance, maneuvering around a bit, and resting by minimizing unnecessary motion in preparation for the next short flurry of frenzied activity, and it’s actually kind of tricky to model that.
In CDDA terms I suppose you could try to model something closer to ‘real’ combat behavior by having the stamina bar both drop and recover far more quickly, with serious penalties for trying to fight with it depleted, encouraging short bursts of activity dispersed with evasion and defense.
Real life has the concepts of both short and long term stamina (mostly represented by oxygenation vs the buildup of fatigue poisons, IIRC). The first is lost and recovered in seconds or minutes, while the latter takes longer to build up, and hours (or even days in severe cases) to dissipate.
It’s also worth noting that physical fatigue is generally a separate concept from mental fatigue (sleepiness) - you can badly fatigued in one category while still relatively fresh in the other - though both are obviously addressed best by getting a good night’s sleep.
Not sure if there is much interest or benefit in modeling that level of detail in CDDA, but if any game was likely to try, this is near the top of the list. 
EDIT: How did we get here from multi-tile monsters? Oh right. Realistic movement rates. Sorry for the rat-hole. 