No, I dont think simplication is needed. Those railcards which are generally available to anyone without a pre-requisite are very simple and have a defined cut-off. There is no confusion on timing there at all to have. These include Network, Friend and Family, Two-Together etc.
Simplification already exists in the sense that a Network card exists and (based on what the posts in this thread say) the sanction for mis-use is just an excess apparently.
The ToCs have (and I know I will get a lot of flak for this) in their generosity given additional discount to some groups but those additional discounts have come with additional restrictions. If one doesnt want to get tied up with additional restriction, then feel free to use a railcard that has fewer.
Even if you go through the Disputes forum, most of the railcard issues are those with 16-17 ,18-25 or 26-30. The incidences of those with veteran card, senior card or network card are very few. Even then, most of the disputes are deliberate attempts to save a few quids and then complain when caught. Maybe its a generational thing that under 30s can't accept that one has to read T&Cs. If one cant take the extra effort to acknowledge that if tickets are sold at different prices, there must be something different in them, then there is nothing ToCs can do which will change the behaviour of the user.
What next, demanding to use Advance on a peak train and expect to pay just the difference in fare, because the ticket didnt specify the time zone!