There is an option for the "Default Profile". This is when opening a new gnome-terminal instance.

When you open new tabs/windows within an existing session using the shortcut keys, it creates a new tab/window using the profile from which you created this tab/window. 

This works fine for Profiles which runs shells, like /bin/bash, since it just reproduces it with your customizations.

However, you can have specific programs setup as profiles, like SSH proxies, IRC clients, minicom sessions and anything else that's not a shell. This is very convenient, as it acts like shortcuts to complex setups, which saves typing and simplifies access to these setups. Another benefit is that you can have special configurations for them as well, so I can have my minicom sessions with different colors/titles depending on what I'm connecting to. Very good feature.

The problem is, though, that when I'm in one of these profiles and use a keyboard shortcut to open a new tab, then it tries to reproduce this profile. For some programs this just causes conflicts and the new session closes, some close so fast it's just a flash, and some completely mess up both sessions.

It would be convenient if there was a per profile feature that disables the new tab behaviour. So you would enable a checkbox, something like "New Terminal opens Default Profile". Then, if you're in a profile with this option enabled it would open your default profile, as when you open a new gnome-terminal session.

This would really be useful, because I have many such tabs, and when I'm in one of them and I want to open a new shell to for example look at a file, I have to first either (a) navigate to a normal profile using <Ctrl>+<Left|Right> and then press the new tab shortcut or (b) use the mouse to open a new tab with the default profile.

What's worse is when I don't have a single shell profile, like when it's a new terminal. I use my keyboard extensively, so when there isn't a shell I'm forced to use the mouse. Besides, I usually have tons of tabs open, and to first have to locate one so I can open a normal shell isn't always viable. It's then quicker to just use the mouse.

So such a feature would be great. 

To quickly get access to this feature, you can perhaps add a smaller one (Before adding the complete one) which completely disables this duplication feature, and ALWAYS opens the Default profile. Even this would work better, as this would cover to optimize at least 90% of the situations I usually run into.