Mechanic is okay, sort of reminiscent of Fractal in intent. The problem is that this card's quality degrades rapidly if your deck is over 30 cards and/or you have fewer than 6 copies in the deck. I also see no point in the unupgraded card not having the Combo ability. It would be better to have Combo on both and have different unupgraded and upgraded versions of the Divine Spirit.
Overall though, this mechanic would be better if it was based off of the number of any type of cards you played this turn and it only produced 2|2 Spirits. You can see the Storm mechanic in M:tG for example, which copies the spell for each card played before it (excluding lands, or in EtG, pillars/pends). Even if you wanted to make a series of Combo cards, EtG doesn't have the card base to support archetypes that are so exclusive.