Is there any 'advanced' debugging available for Views? I know Views can show you an SQL preview, various performance statistics, and other SQL queries performed for live previews; I'm looking for something a bit closer to the bone.

The use case...

I'm writing some custom handlers for various entity/field properties (doesn't matter which types, it's all very generic stuff). I'm trying to get these handlers applied to fields in a Search API view, and the 'standard' method of implementing hook_views_data_alter() and changing the field handlers to the new ones isn't working. I think perhaps because $data['commerce_product']['title'] (for example) isn't what the Search API view actually ends up using, so replacing the handler for the entry does nothing.

So I need to know what fields are using what handlers, and preferably anything else that would help me to understand why Views has chosen one and not the other.

I know I could theoretically do this by looping through the field definitions in a pre_render hook or similar, but I'd rather have a solution in place for this any time I need it, as opposed to having to write/copy code for it every time. It feels like such a thing should exist and that I just haven't come across it yet.

Is there anything either included with, or that can be tacked on to, Views (version 3 specifically) that will help with this?
The admin/reports/views-plugins show a table with every plugin used by Views, noting which views use them. And if you want to figure it out programmatically, you can check the code for that page.