Up until not all that long ago I persevered with mix-my-own soluble and isophane injections, with a mixtard-50 pen to use in the evening when out for meals, etc. When I was younger and less desk-bound (and just bascially on the go more) this worked fine (I was always running low, which is easy to treat by eating), but as I've got older and unfortunately more chained to a desk, it wasn't working so well (not least needing to snack lots while doing less) so I finally made the switch to basal/bolus and wish I'd done it sooner.
Basal is one or perhaps two injections per day of a very long acting insulin to give background coverage, and bolus, a fast acting insulin, is taken for each meal and for any correction doses.
I'd not go back out of choice, but it would be doable. I do think that being able to chose your own ratios makes life easier, though I suppose if I had mixtard 30 and mixtard 50 available it could be made to work (for the evening I always really wanted a thing which doesn't exist - mixtard 70.) I used to vary my doses day by day to give some ability to tune to my activities & trends, but even with a choice of fixed ratios it would probably still work ok.
The major disadvantage of mixtards and my soluble/isophane regimen was that the short acting is not as fast as modern short acting insulins, and the long acting is not as slow as modern basal insulins, so it was very much more a case of roughly fixed meal times and reasonably fixed quantities of carbs along with snacks/exercise in between to maintain blood glucose.