I feel the customization with HTML templates is a lot more unique - but I wanted a certain gadget, on my blog. I upgraded my template in order to add the gadget, and copy its coding. After reverting back to the Classic template, I placed the gadget into my HTML. How do I get the gadget to work?This blog owner does not understand the differences between HTML and XML.
Many Blogger accessories are written in XML.
XML code won't run, in an HTML only environment.
With an HTML only template, your blog won't have the XML libraries which support XML coded accessories. You can't use an XML coded gadget, in a template that only uses HTML.
The benefits of Layouts / Designer class templates will offset the drawbacks.
It's time to move forward, and try out Layouts / Designer class templates. Unique customisations, or not, what you will get, with the newer templates, will make up for the differences.
The XML gadgets, that will only work with Layouts / Designer class templates, are just a small reason, to move forward.
Multiple environment template support cannot last forever.
Supporting multiple versions of Blogger code requires resources - and all resources are finite. One day, Blogger Management will realise that the cost of supporting HTML only templates exceeds the benefits.
Whether the decision to end HTML only templates comes in an emergency - or simply a long term strategy - support for Classic templates will end, one day.
When the end comes, you will not enjoy the experience.
I helped support the migration from FTP Publishing, in 2010 - 2011. You do not want to be part of a similar scenario, when Classic to Layouts migration becomes a necessity, and has a deadline.
If your blog uses an unconverted Classic template, move forward. It will be easier than you think, right now. Do it this month - or this year. Don't plan on waiting out the decade.