Nice job keeping the frog on there! That's really smart (that's sincere, not sarcastic. =). However, there are two outcomes to leaving excess frog. You'll especially want to be aware of them because your horse had an abscess blow out at the heel:
1) The old, extra frog tissue there, acting as a pad, should encourage the new frog to grow in. Once the new frog does start to grow in, the extra 'compression' it gets (via the old frog material) might help it gain density and quality until such time that you (or your farrier) deems it appropriate to trim out the old frog, or the old frog is ready to shed out.
OR 2) The old, extra frog tissue there, acting as a pad, starts to cause excess pressure and soreness as the new frog grows in. YOU DO NOT WANT THIS. You want to stay away from anything that might cause another abscess, obviously, but there's another issue with the hoof being generally sore...particularly if the soreness is in the heel. Horses that have been heel-sore sometimes get the idea that they can tiptoe around and not use a heel-first impact. (Why would you do something that hurts?) This tip-toeing around DOES start undesirable hoof growth patterns - more wearing of the hoof at the toe, and that can lead to an inability to 'grow' hoof wall at the toe, and can (down the road) lead to founder. So prevent heel soreness at all costs. Don't be shy about shaving thin layers off of the shedding frog, when appropriate. If you use a farrier, be sure to discuss this.
Furthermore, one good thing to do (to check on proper hoof growth) is to measure collateral grooves at the heel and apex of the frog, both sides. Here's how to do that and some tools (other than the lollipop stick) that can help:
How to: Measuring Collateral Grooves - The Laminitis Site
Tool that I'll likely be getting: JH Forge - Hoof Evaluator
Tool that I own but had to customize (it was too thick to fit in the collateral groove): https://www.precisionhoofpickusa.com/
Sometimes 1" depth at the heel and 3/4" at the toe are appropriate, particularly if you have a bigger horse. Given that you're working with a 2yr old warmblood, the 3/4" depth would sounds appropriate. If you feel he needs more heel in order to prevent soreness, don't be bashful about leaving up to 1/4" wall above the sole plane - just make sure you leave that much all the way around.
If your horse is showing signs of lameness, it might be excess frog pressure OR it could be that some infection got deeper in there than you suspected. Soaking for about 5 minutes with 'white lightning' treatment can help ensure hoof health, and it's safe on frog tissue. Triodine is a frog-safe disinfectant you can use to squirt in there, and it's a mild antifungal/antibacterial mix of iodine that 'sticks' very well to hoof tissue. (Triodine stains, watch yourself.) I, too, love 'Pete's Goo' to prevent infections and thrush.
Note about farrier's formula: it contains iron, and horses are tending to have too much iron in their diet rather than too little. Too much iron (and mineral imbalance in general) can be a culprit of hoof problems, and can encourage thrush (one indicator of high iron). Proper protein (amino acids) and mineral balance are food for hooves.