Its been a while, but we used to work with Magento quite a bit. We found it easier to modify exsisting themes rather than building our own from scratch. Due to this reason, we used WooCommerce almost exclusively for most projects however recently we considered a new project with Magento due to its ability to work with 3rd party point of purchase software, but we are concerned with the ability to theme Magento the way we want.
What is the current opinion of themeing Magento? Is it more modular? It seems that Magento was not very flexible for designers, is that still the case? Will there be too much development overhead for designers to wrap their heads around (and therefore limit their imagination)?