There is nothing wrong with a MK 4 3.5-10 in mil/mil or moa/moa. You don't need a bunch of whiz-bang shit on your scope, but decent glass and excellent tracking. Illumination is a nice feature, but not absolutely required on a good SFP scope, it is mandatory on a FFP scope though.
First off, if there anything wrong with the older optic?
It can be sent back to the factory for a cleaning and once over, you can also change the reticle etc... at minimal cost.
There are other companies that offer excellent agency pricing.
Sightron, Burris, Bushnell and Vortex ALL offer excellent LE prices.
This would be an excellent option and the agency price is fantastic:
https://sightronusa.com/index.php/product/siiiss3510x44lrirmoa/
Sightron has rather fine reticles, so illumination is a must.
I ran a 2.5-17 STAC for a while on my personal duty rifle (capped turrets are recommended here) and I really liked it.
The reason I don't recommend the mk 4 4.5-14 is you really need to get as close to 2.5 or 3 power as you can for field of view on close shots.
Also, keep in mind minimum focus distance, many scopes have a min distance of 50 yards, sightron offers 10 yards, which is excellent, Vortex offers 20 yards on the PST 2, which is very good.
You could easily get into a Vortex razor Gen 2 for less than 2000 and you would be hard pressed to beat it, however, I have talked to numerous LE snipers and most of them didn't know much about optics and really weren't that interested.
Apply the KISS principle here. More magnification is nice, but not necessary for LE work. a top end of 9 or 10 is perfectly suitable, but I personally prefer 14-15.