They did it just to introduce more "new" mechanics-cards to the game. In the end they had to make 2, 3 even 5 times erratas to old cards. That made the game MUCH more complicated and frustrating in TCG tournaments, were you had to tripple check if the card actually targets or not.
This cards is over 10 years old, old cards tend to be bad compaired with newer hyper-complicated cards. Konami thought back then that this card was already too "powerfull". In fact was to useless.
If you have at least 1 rebounder or a midfielder in ur hand.2 lady's of the wasteland in ur deck, but 1 in the hand, and a Paleozoic marella you can setup for a turn 3 or 4 turnover. Lady of the wasteland can special summon herself back on the field, if there is 2 monsters on the opponents side, then when all the monsters attack summon perfect ace or midfielder on the field during ur end phase.
Which means the DARK Dragon-Type bit is going to be useless for a long time, you'll only ever going to summon a DARK Plant-Type monster instead.
Since there's pretty much no other DARK Dragon you'll want to play in Predaplant deck.
This card is not exactly a boss monster (Primebanshee and Memorygant are Altergeist's true bosses), but yeah, Konami does have an obsession with that sometimes.
Wouldn't it be too strong with 300 ATK AND 300 DEF? I'd suggest to just switch the current ATK & DEF stats. I don't want to see such OP cards at all in PVP.