I have actually seen 4X CA with 1 10Mhz B25 and 3 20Mhz B41 channels, and the upload was still no more than 5Mbps. Also had good signal strength. Also, download was not that impressive. Maybe around 80Mbps.
Now, maybe they are still "tuning" everything.
The negative press on Sprint in the merger process should be a significant factor in churn. Converting former Clear sites to triband should have had a significant performance impact yet has not dramatically appeared in Rootmetrics results. The rarity of B25 + B41 + B41 CA is a factor since that would solve band 41 upload congestion (5g would be even better). In my market attention is shifting to software updates. VoLTE came to Magic Boxes last week. Overall network improvements might just be a multistep process yet to be completed. The competition does not stand still for Sprint.