Super Saiyan said:
Dende was ultimate savage and wished Piccolo to Fake Namek instead of real Namek. Events go down the same until Piccolo' s arrival. Instead of Piccolo arriving, Goku is fully healed and joins Gohan, Vegeta and Krillin. Freeza is in his second form and the gang won't give him time to transform further. Would they be able to pull out a victory somehow? Gohan is at his post zenkai level with potential of rage boost similar to one seen against 3rd form Freeza. What happens?
Goku said 'Curses, I can't wait till my wounds are fully healed' and was about to get out of the healing chamber and step in, but then Piccolo showed up. If Piccolo had not shown up, a semi healed Goku would have arrived in his place. His power level depends on whether you think his zenkai requires full healing to take effect.
1.
Goku does not get a zenkai due to him not being fully healed.
Freeza obviously slaughters everyone. Kami uses a combination of wishes to put everything back to normal (restore Namek dragonballs, revive everyone, bring Piccolo back to Earth etc). Freeza does not realize that dragonballs came back, so he has no reason to attack Earth. Nevertheless, Alternate Trunks shows up, warns them about Androids and reveals the secret of SSJ form. Over the following 3 years, Goku and Vegeta both train themselves to SSJ level.
The first part of Androids Arc (19/20 are defeated, 17/18 stomp everyone etc) happens with no major changes. When Kamiccolo goes to investigate at Ginger Town, Cell kills and absorbs him, because he's weaker than in canon (no Nail).
When Androids arrive at Kame House, Krillin and Tenshinhan stall them till Cell arrives. Tenshinhan is killed, because Goku does not have IT. At Cell Games, Cell destroys the planet when he selfdestructs, returns as Super Perfect Cell and goes to explore the universe.
When he encounters Beerus/Whiss, he becomes their student and reaches SSJ Blue level. At U6, he beats Hit. If he causes Zamasu's jealousy, the Zero Mortal Plan succeeds. If not, he befriends Zeno and gives him some Cell Jrs to play with so that he won't erase universes.
2. Goku gets a zenkai.
If Goku's PL is at the millions, even if not fully healed, he stomps 2nd form Freeza. After that, they return to Earth and events go similarly to Case 1.