the chemistry toy would be fun but it would require alot of programming and a new particle interaction code for unknown particles, it would be very time consuming, and would probably branch off the old one.
yes, but that was an example, we wouldn't have the time or the manpower to add all the possible mixes by hand, and the code for mixing elements from scratch would be way too time consuming to make.
The amount of time that a programming task takes depends greatly on what language you are programming in. In C, which is what PT is written in, development times for complex code can be ginourmous. Whereas, in a language such as Python (my personal favorite) a program such as a simple web browser can be made with under 100 lines of code and with as few as 2 or 3 hours of work.