Andrew-
I split my base volume currently as I rehab my knee and occasionally I’ll split my strength training depending on duration and how well i’ve fueled preceding the workout. I split to make sure I’m getting quality form and recruitment during my runs so that I don’t start losing form and stressing connective tissue unnecessarily.
I’ve noticed that with the splitting I get much better quality in terms of form, recruitment, and overall energy levels (obviously, right?) This is true for both my base workouts and my strength training.
I do lose more time to warming up and cooling down, though. It sounds like this isn’t an issue for you, however. There is also a nagging feeling that I’m losing an intangible amount of resiliency because I’m not spending as much time working while fatigued.
I feel like the improvement in quality of work done is worth the extra hassle.