[Nazzareno]

Manual coding is getting very inefficient since it takes hours plus it requires a lot of testing (ie with litmus or emailonacid).

There are modern alternatives to manual coding both for developers (embeddable editors for SAAS) such as beefree, unlayer, chamaileon, stripo and for email designers like beefree, stensul, knak, stripo, taxiforemail...

[herbst]

To be fair I am using a very limited 'style' for all my emails and usually they just work. Everywhere

In my experience the more shiny the email is, the more logos and whatever components are around the actual content the less clicks I get. So i try to be just a branded level above a text email.

[iamacyborg]

A lot of those template systems you just mentioned require an email dev to create brand appropriate modules.

Once that’s done it does drastically improve the speed of email creation though.