Besides that, as a secondary thought I think the interlock preventing forward thrust during at least one engine reverse (and ALLOWING spoilers) and/or vice versa: preventing reverse (and spoilers) during one engine forward thrust - makes perfect sense and should be introduced.
There is one problem with this idea, that being the case of an undesired (i.e. accidental) thrust reverser deployment during takeoff after the go/no go decision speed (V1) has been reached. In this case, the crew would be required to continue the takeoff, because there may not be enough runway left to stop the aircraft, particularly in a "performance limited" case. An undesired thrust reverser deployment would result in the affected engine thrust automatically going to idle, thereby limiting the effects of the deployed reverser, and making the aircraft flyable. So, at a time when the crew would need the thrust from the remaining "normal" engine, you would take that thrust away. This could in fact, result in exactly the same accident as Cononghas, and aircraft at too high a speed overrunning the runway with tragic results.
I am not opposed to taking a careful and detailed look at the circumstances of this accident with an eye to improving technology to reduce the chance of a repeat event. But, as has been said above, this must be taken with great caution, because every "improvement" brings with the possibility of introducing new error-producing conditions.