1) add "running" attribute
use case:
many templates define "running parameter. a good example is Template:Track listing on enwiki.
currently, the templatedata is tedious and repetitive. instead of having to define separate parameters title1,title2,title3...title20,
rationale:
in many cases the template is a shim above scribuntu, and in those cases the range is not really bounded, e.g. "track listing" supports as many "titles" as needed, while the TD has to stop somewhere (in this case 20, which is not enough for all actual use cases).
furthermore, this does not provide meaningful information to the tools. i'll use an example: in hewiki, we used a "template wizard" long before the introduction of VE and templatedata. we did have "running" indication, and when editing a template with parameters of this type, thee wizard always presented exactly one empty parameter for "titleX", so once the editor added any value into "title11", it displayed the "title12" field and so on. with current TD, the wizard is not aware of any connection between title11 and title12, and has to either show or hide both, instead of exposing the latter when the former becomes non-empty. similar issue pertains to "linting" tools that use templatedata to detect errors in templates parameters.
2) add "exclusive" attribute to parameters with "suggested values"
(this request was expressed before)
use case:
"suggested values" are primarily used with parameters that are fed into {{#switch "template condition".
in actual usage, "switch" can have 3 distinct behaviors when it's fed an unexpected value:
-- simply ignore it and behave as if no value at all was fed (no "default" clause)
-- use the unexpected value
-- generate an error (something like:
```
| #default = {{error|bla bla bla}}
```
IOW, a value outside the list is either expected or an error (first case is also an error: editors expect parameter values to have an effect).
templatedata should be able to indicate whether for this template and this parameter it's "kosher" to feed a value outside of "expected". again, this is useful for wizards and linting tools