I know this wish may sound debatable, but there's something I find really uncomfortable with Gradle right now.

Suppose you have:

myProp=false

and:

includeFlat 'subprj'

and:

if(myProp)
  println "master: true"
else
  println "master: false

and:

if(myProp)
  println "subprj: true"
else
  println "subprj: false

If I run the script, the following is output:

master: true
subprj: true

This is because myProp is set on both master and subprj as a string property and a string property always evaluates to boolean true when the string is not null and not empty.
Under the point of view of the "least surprise", this is already something that the user will discover by banging his nose against the wall (I'm also wondering why Groovy is not "smart enough" to consider "false" as boolean false...). But it's even more annoying if you consider that changing master/build.gradle in the following way:

myProp = myProp.toBoolean()
if(myProp)
  println "master: true"
else
  println "master: false

isn't enough yet, because myProp is independently set on all the projects (and not only on the root one) and hence the output will now be:

master: false
subprj: true

So, you eventually have to do:

allprojects { myProp = myProp.toBoolean() }
if(myProp)
  println "master: true"
else
  println "master: false

which is overwhelming, IMHO, unless you remember to put "toBoolean()" method call in all of your "if" statements instead.

So, what do you think about the idea to make Gradle "detect" boolean properties in gradle.properties and automatically cast them to booleans before setting them on the projects?
This might be extended to integers and floats/doubles, for instance, but I think this might be less vital, since it's less likely that trying to use strings instead of numbers will affect users in unexpected (and sometimes hard to debug) ways.