I have an opinion on this as I hunted 4th season deer the last two years on 13+ point (non-res) unit (2 tags in 16' and 1 tag in 17' and shot one buck in 16'). When you spend that many points, you are hoping if you hunt hard, you will see a number of decent bucks and hopefully one good one.
I feel very strongly that there should not be a full 5-day season overlap between the 4th season deer and 4th season elk hunts. From comments above it sounds like there isn't much elk hunting pressure, that is totally not true in the unit I was in. I was in the same areas at the end of 3rd season scouting and saw more elk hunters during 4th than 3rd both years. I am guessing the 3rd season elk hunters were either higher up or had given up.
Yes, the deer during 4th season are rutting and yes many have moved down with the does near their winter range. You have to hunt the does during 4th and often times the does are down low and close to quad/ATV access points where elk hunters are preparing to drive their ATVs into more remote areas.
The reason I feel there should not be overlap is based on three instances where elk hunters were the primary reason a buck was not harvested.
1. 2016: preparing for a shot at a 180-inch buck just before dark and an elk hunter pulls up and starts yelling at a child. Deer went into thick stuff and did not come back out.
2. 2016: Last day, just spotted a 210+ buck rutting with 3 does and settling in for a shot 30 minutes prior to legal shooting light ending and an elk hunter rides in on quad and starts "teaching" his son how to load the quad on the truck right at prime time and the deer hear them making a racket and go into thicket. They came out at dark after the elk hunter left, but way too dark to shoot.
3. 2017: went back for the 210+ with another family member and had a very difficult hunt only seeing 2 4X4s the entire hunt. Many big deer were already on private and only small bucks on public. Hunted where the 2016 big buck was seen and had 7 elk hunters lined up there with an outfitter hoping for a herd to move that way from private.
2017: last morning, saw a 180+ at just under a mile with 10 does and was moving on it when an elk hunter drove up and stopped to look and the deer went into the thick trees, only the does came back out.
I am not as upset about the 2017 issue as the 2016 issues that were just crazy yelling and carrying on by elk hunters right at prime time.
My suggestions would be either to add two days to the 4th season deer (7-day hunt) to end 2 days after 4th season elk, or just make the 5-day hunt end 2 days later than 4th season elk so there are only 3 days of overlap. My 2 cents.