I'm not sure I understand your suggestion.
Currently with the APL+Win CSE, one can use )edit to create a C# script (e.g. in an APL+Win text array variable myScript) and then type cse' Exec' myScript [Enter] and immediately find out if the script ran successfully. The APL+Win workspace containing myScript can be )saved or the myScript variable can be stored in a file for editing at any time. An analogous procedure using Microsoft NotePad to create a physical text file, e.g. called myScript.txt, can be used to execute a C# script by typing
cse 'ExecFile' '...\myScript.txt' [Enter].
(a) Are you thinking of a browser-based GUI where the user would type in a C# statement, click the Enter button and the server side would execute that statement reporting the result or error message? Where would APL come into this picture? This option would also require a persistent server session for the duration of a user's browser session.
(b) Are you thinking of an APL+Win form with a multi-line edit box which accepts a C# statement and then executes it on the user's local machine on which APL+Win is installed? This is precisely what the Cielo Explorer in VisualAPL provides, but VisualAPL is Unicode-based and depends on Visual Studio to display the results of a C# executable statement. VisualAPL provides this beneficial feature by being integrated with .Net, but in doing so must comply with .Net requirements, thereby diverging from traditional APL implementations.
If a programmer, who is not a current subscriber to APL+Win, wanted to try out the CSE, a fully-functional, time-limited demo/evaluation version of APL+Win can be requested from firstname.lastname@example.org
I am not sure that 'entice' is the correct word. Some APL+Win programmers will use the CSE and C# when they ascertain that it provides them with a specific feature useful to their application that (1) is only available in .Net or (2) is more conveniently available in .Net. Some APL+Win programmers will try the CSE and C# out of curiosity. The APL+Win CSE system function is designed to make these uses quite easy. The important effort now is to identify examples of .Net/C#/CSE use that are potentially beneficial to an APL+Win programmer.
We're talking practical, time-sensitive programming here. If APL+Win can get the job done, great. If some C#, via the CSE, would make the resulting program better or easier to build or maintain, great too. If the xyz programming language is required, learn it and get the job done. It's best to avoid writing a paean to any specific programming language.