The scimitar currently is a ramjet missiles, advertised to be able to reach speeds of up to mach 4, giving it an extended and impressive range increase at the cost of price, theres just one issue though :
It NEVER stops accelerating
Taking inspiration from other ramjet/airbreathing missiles, also known as the mbda meteor and the prototype and never build aim-52 acimd, those 2 missiles have a particularity that could be added to the scimitar, increasing its deadlyness while staying realistic :
Throttle control.
Both those missiles have this option, once the acimd or meteor reached the wished speed of mach 4, the missile would throttle down to keep that speed, conserving fuel
Our scimitar, like the meteor, seems to have about 60 seconds of fuel after the initwl booster, while yes it does reach, mach 4 like advertised (everybody thank kramenka industries please) it never stops accelerating, even reaching mach 6 at high alt and losing it thanks to an early altitude drop
So here's my suggestion : giving the scimitar throttle control could not only increase it's range but also stay realistic, for a twist, it would slam itself into max throttle once arriving into terminal phase to spend those last % of fuel going as fast as possible, basically importing the terminal boost of the agm 99 (98 for @restive kelp) and also letting it change its throttle to keep preserving fuel during flight.
No idea how coding works, but i would assume that the scimitar would have a "fuel value" and a "throttle" value, if mach 4 is acheived throttle value goes down and fuel goes down slower, letting the missile hold between mach 3.90 and 4
This could be done anytime thanks to the "additional missile mechanics" in the roadmap, dont hesitate to share your ideas here !