Even instructors screw up - we're people too.
The Senior is a wonderful plane, big and slow enough to allow lots of time for corrections, and large enough to see when it "wanders". The instructions aren't lacking, but there are things you can do to make it "more better". ie: pin the hinges, use high quality hardware, fuel and/or air filter (if needed), beef-up critical joints (
), etc, etc.
ALWAYS, ALWAYS, ALWAYS Preflight. EVERY time. This includes range(motor running too), controls, airframe, battery, servos, and anything else you can possibly check without x-ray. We do the same thing on 1:1 scale, minus the range check of course.
As far as taildragger vs. tricycle, I won't even try to add anything besides it's pretty much up to you. If you like taildraggers, fly taildraggers. same-same with trikes. The only thing it changes is how it behaves on the ground, and it shouldn't be there(on the ground) for long.
The only reason to have landing gear is to keep the belly off the ground.