give a definitive value of steals and caught stealings?
As a general play, the rule of thumb historically is that you need at least a 66% success ratio to make the stolen base a good play. In times where lots of runs are scored, that number goes up to %75 or so. That's about where we're at right now. In times where runs are very scarce it may go as low as %60 or so.
That's as a general play. There are several stats from different sources that make this kind of adjustment using slightly different coefficients based on run expectancy tables.
The thing is...the value of every steal is most certainly not the same. There most certainly are clutch and non clutch steals. Sometimes it's just a nuisance play and sometimes the game can turn on it. Accounting for that kind of information is, frankly, a bear and to my knowledge nobody does that kind of thing with win expectancy tables. Well, to be more specific at least not easily available in the public domain.