I will pass this feedback onto my supervisors. However, read my explanations below:
1. This is actually rather quite easy to do, yet some of our users do not follow them. For example, the majority of users issues are caused by either poor cheap hosting packages and/or plugins. In regards to hosting, you most certainly get what you pay for, if a user purchases shared hosting which is usually very cheap, their site will perform badly and will likely run into issues with certain features or functions being disabled due to a shared hosting environment.
The use plugins and the issues caused by them come from the fact that a lot of users install an insane amount of plugins, that for the most part do not need to be installed or aren't really required. The record so far was a user who had issues with his site not working as intended, when we investigated the problem we found that he didn't disable all active plugins (he refused), but when we checked he had 373 plugins active, this is just insane. No one needs this many plugins. The problem with installing multiple plugins except for the mains ones such as W3 Total Cache/WP Super Cache, JetPack, WooCommerce to name a few is that sometimes these plugins are either badly coded (not following the WordPress standards or they conflict with other plugins. The problem with this is that most users believe that this is an issue with our product and not the plugins themselves.
Another thing, users for the most part fail to do when using custom code is to not check that it is valid and/or add scripts to sections that aren't suppose to work with sections such as adding an iFrame or a script to a TextBox section. A TextBox is suppose to house text and basic HTML, nothing more. Following the above, will help drastically with your sites performance and reduce the problems you encounter.
Host - We recommend FlyWheel, they host PageLines.com - http://getflywheel.com/
HTML validator - http://validator.w3.org/
CSS validator - http://jigsaw.w3.org/css-validator/
Code Editors - We recommend either Atom.io (by GitHub), SubLime Text 2/3 and TextMate. All of which have addons/extensions/packages called Linters, these linters check your code for errors, they can be configured to do this on the fly. I highly recommend using one, I personally use Atom.io or Sublime Text 3beta.
2. Our staff provide very limited customization support. We do have a resources page on our documentation which lists some of our store developers who are happy to provide customization support, custom sections for a fee. http://docs.pagelines.com/resources/
3. See above.
The reason our staff only provide limited customization support is that this is how most WordPress theme providers support work, WooThemes, Elegant Themes and RocketTheme all do the same thing, in-fact some of them do not provide any customization support at all. Also in-regards to a screen sharing solution, we did a trial of something like this a few years back when Rob was with us. At first, it looked like it was going to be a cool extra support alternative. However, after few days, we became aware that the screen share service was being abused, users we requesting assistance to multiple problems, most of which were documented as well as including customization support which was not part of the service.
The very same thing happened when we launched the Live chat service, which was initially mean't to be a live chat community for all users who were part of the club membership, where they could discuss issues or ask questions amongst themselves, share ideas and the chat channel was moderated by our staff. However, users were just logging on and asking a question which they had already posted in the forums, but because they didn't get response within the first few minutes of topic creation, they decided to ask in the Live chat, which our staff kindly resolved. However, we then found that staff members in the forums were also resolving the same issue, so we were answering the same questions/issues multiple times. Another problem was that users starting to abuse our staff when we informed them that customization support wasn't provided in live chat.
However, some of these problems were likely our fault as we didn't police the services strictly enough. So I will pass your feedback to my supervisors.