Neither of those "benefits" comes as a result of your "simple, inherited constructor". You get them for free regardless. I think any further expression of my scepticism is redundant.

Well no, you don't get name/value pair argument handling for free. No, you don't get consistent internal object structure for free.

Really have no idea what you're talking about getting for free. Perl is work, man. Only thing that makes a difference is designing where the work gets done.