Warframe was actually really good at the very start (closed beta), but it was very proof of concept and lacking in content. It's issues began when it constantly overhauled its systems and started making things needlessly convoluted.
When it launched it was in a pretty bad state overall, despite having a lot going for it, and since them its grown tremendously (even if you need to use the wiki as a manual...).
But yeh, most of the better GaaS service games you can think of now either had a poor launch like Anthem, or a previous iteration that they learnt from.