Our TT is 10 years old and we have never had any electrical receptacle issues with hair dryers, micro waves, toasters, coffee makers etc. in any of the outlets.
The RV industry has enough issues without inventing more. That is like blaming the toilet maker because the worker used too long of a down tube and it would not flush properly.
With regards to the OPs question, I believe our electric ceramic heater cost around $20.00 so trying one is not going to break the bank.
As mentioned the oil filled unit are nice but a bit bulky for our under the table use.