Anyone who knows anything about aircraft design realizes that every aircraft is a trade-off on performance, speed, weight, etc. One very interesting NextGen type design is the new ultra-efficient AD-9 Prototype.
Recently, Mark from the UK looked at the design and stated that "having a jet engine and a retractable lift system is a great idea, but wouldn't having a small bulge on the nose and have retractable guards to the engine but leave the engine fixed save a little weight in the design whilst not compromising the aero shape?"
Well, yes, perhaps, and that is a decent point, although the extra bulge in this case could be done in such a way as to create very little drag or relative airflow. And at the slower speeds for take-off and climb out it is not as big of an issue and then it retracts into the fuselage.
Also, since there is only one engine aft, and centerline thrust, the jet engine is set on the opposite side of the direction the torque is pulling the aircraft, thus the pusher configuration can run now at full power with no torque issues. Indeed, some of these smaller jet motors are not all that heavy. Shorter take-off, shorter climb-out, has lots of advantages, yes, too some disadvantages as well, for instance what you have mentioned.
Mark, later apologized for his critique on the prototype concept, still, you see, I believe we should question EVERYTHING and leave nothing off limits, so, I see it as a good question, and you have a point too. I had some questions myself on the design.
Most aircraft of this type have lightweight nose cones, and the thrust from a small jet engine has design challenges, beefing up the front of the fuselage, that is bothersome, adds weight, not to mention the jet motor in the front, screwing up what we'd consider proper weight and balance for such an aircraft.
Although it does help keep the fulcrum forward and offset the CG due to a large turbo prop pusher way aft on the empennage. Personally, I'd want to change out the entire vertical/horizontal stabilizer system with a circular system, as it would serve dual purposes, funnel airflow, and act as a stabilizer system to decrease yaw - and for control surfaces.
A small canard system may also be needed on that design? Still, it is unique and a worthy idea, worth pursuing, with or without the changes, at least a small scale prototype, or a serious of them - large RC size, or 1/3 scale. Might make a bitchin' UAV concept, who knows, or a flying car type system - triangular wing configuration, unfolding. Indeed, I hope you will please consider all this and think on it.