On Tuesday, February 19, 2019 at 5:58:47 AM UTC-8, wrote:
Drilling through the inner sliding tube is a pretty bad idea IMHO because it weakens the tube and adds an unwanted stress riser. A better solution is to make a two-piece collar that can clamp over the tube between the tongue housing and the hitch, thus preventing it from compressing.

Yes.
Besides the odd idea of disabling the trailer brakes, drilling holes in the tongue to promote tongue failures we've previously witnessed seems misguided.
It seems to me that failure mostly occurs with a heavily-sprung tow vehicle, long cantilever behind the rear axle, or an overweight trailer tongue. Combinations of those are a gamble.
The max weight rating is on the tongue, most are 100kg.

OP:
One thing I imagine electric brakes would be useful for would be engaging them independently of tow car brakes if there is instability.

Personally find AlKo trailer brakes pretty easy to maintain.
Perhaps change the tongue compression damper more often? If you live where things get rusty, routinely treat the Bowden cables with LPS-3. Grease fittings are there to be used.
Download the trailer manual (Spindelberger have it available, perhaps Anschau)
Jim