8.5% tax on revenue is really good. And this is very specific: it applies specifically to SaaS businesses, most revenue-based rates are higher.
If you decide to sell your business, assets are taxed at 3%.
The 8.5% thing you talk about is not really that great (it's revenue based so it's out once you have significant costs/partners you pay). It's done to simplify accounting. It only makes sense for small one person companies and it makes sense to incentivize people to start businesses - a wild concept in Germany (or most of other EU countries).
I would be inclined to disagree — it is absolutely wonderful for solo entrepreneurs. You might say "it only makes sense for small one person companies", but that's exactly what my business is and intends to be.
You can easily run a SaaS business with 90%/80%/75% margins (gross/operating/net), which I think is really hard to beat anywhere in the world.
For people who want to stop working for "the man", become in control of their lives and earn money from a SaaS business, this is great.