here are a few suggestions/complaints from me, off the top of my head. i'll try to add more when i remember something. my lazarus version is 0.9.29.27722 (at this moment).
flaw - stringgrid border - win32 widgetset
stringgrid border flickers on resize (unless flat property is set but we don't want that)
flaw - form border on kde4 (posibly other window managers)
form borderstyle bsDialog does nothing under kde4 (gtk2 widgetset) - nothing good that is - form gets the xwindows icon and that's it (still resizable (also with bsSingle), border icons still there).
flaw - message dialogs on kde4 (gtk2 widgetset)
in addition to having a sizable border (see previous paragraph), message dialogs (invoked by MessageDlg function) also sport an ugly crisp icon. isn't it time lazarus said NO to bitmapped images / icons / button glyphs?