Scott, thanks for the feedback. As the platform.sh product manager, I’m really really happy to hear it. The pricing structure is our first shot at getting pricing right. It’s tough business, and we’ll iterate on it, incorporating feedback from yourself and others.
Regarding the developer licenses: we’re considering getting rid of them in the near future. Also, we’re intending to move to “per-service, pay what you use” pricing as soon as we can engineer the the supporting bits around that. I think these two changes will address your pricing concerns pretty squarely.
When we scale MySQL (MariaDB), we do so using Galera Cluster. It works quite nicely, and allows us to take your database from a few CPUs and GB or RAM to nearly 100 CPUs and 180 GB of RAM without ever taking your application offline. This is available to our Enterprise customers.
Solr is scaled using SolrCloud. Redis is not scalable, as you say, but we provide high-availability Redis so that if one instance fails, another takes over (the cache data is assumed to be ephemeral and will be rebuilt).
Hope that answers some of your questions!
Cheers,
Robert Douglass