From an in-cannon perspective, how would the G1 canon have differed had Unicron not shown up in The Transformers: The Movie (1986)?
There are, I think, two big features worth exploring - (1) the change of leadership and (2) the Autobot Moon Bases. Let's start with the latter. We don't know much about the autobot moon bases, but they seem to be largely automated weapons development facilities. It's possible that Ultra Magnus and other autobots we didn't see in the first two seasons of the show fortified these locations during the Ark crew's big sleep, but it's likely that after forming an alliance with Earth to supply energon (presumably more effectively than Megatron's schemes...), they were able to develop these from refugee camps to fortified weapons facilities. Optimus tells us that "all we need is a little energon and a lot of luck," which suggests they were ready to begin an invasion of at least part of Cybertron when the movie began.
It's possible the moons also had an army of Cybertronian autobots who were destroyed, or that they were already on Cybertron waiting for the invasion. More autobots is always a good thing, but given Season 1 & 2 depicted Cybertron as baren, but the movie depicted it as having a robust Cybertronian population... in at least one city... it's not really clear what numbers we're working with, so all we really have to go by are Optimus and Megatron's plans, with Optimus planning full scale invasion, while Megatron plans to... destroy autobot city, thereby threatening the energon supply to the moons and/or undermining the Earth/Autobot alliance. This suggests, at least to me, that this isn't an issue of manpower, but of energon (which isn't surprising, since G1 Transformers was a rather unambiguous reaction to the 70s oil crisis) - if the autobots had a consistent supply of energon, they'd win the war. And guess what? It seems that they do regardless of whether Unicron shows up.
The second big difference is the leadership. Ultra Magnus seems to be battle hardened, but is more of a follower than a leader. He'd likely follow Optimus Prime's plans, but perhaps pause the invasion to rebuild Autobot City. Starscream, I suspect, won't fare much better; I suspect he'll want to shore up support for his leadership, which means two things: (1) small, symbolic victories he can brag about, and maybe (2) sending his rivals off to die. Neither of these are going to tip the war in the Decepticon's favor.
After a short period of relative calm, Ultra Magnus would be back in Optimus's position and follow through with his invasion of Cybertron. Starscream could follow in Megatron's footsteps and try to undercut this by sabotaging supply lines, or pre-emptively invading a moon, but I halfway suspect Starscream will sign a peace treaty at the first sign of a bloody nose, ceding half of Cybertron to the autobots, perhaps in exchange for energon aid. This could lead to a cold war on Earth, as Decepticons try to secure their own alliances, energon, or destabilize the human/autobot alliance.
The real threat, however, is Megatron who obviously still functions. If he gets picked up by the Quintessons or Junkions, he'd return to take over the Decepticons and likely catch Ultra Magnus unaware. It's also possible that disgruntled Decepticons might go looking for him, given the number of witnesses. No offense to Magnus, but Megatron is on a different level, and I suspect that if he's caught off guard, Ultra Magnus might fall, especially if Starscream's machinations really helped to put the Decepticons on a more solid footing.
There are, I think, two big features worth exploring - (1) the change of leadership and (2) the Autobot Moon Bases. Let's start with the latter. We don't know much about the autobot moon bases, but they seem to be largely automated weapons development facilities. It's possible that Ultra Magnus and other autobots we didn't see in the first two seasons of the show fortified these locations during the Ark crew's big sleep, but it's likely that after forming an alliance with Earth to supply energon (presumably more effectively than Megatron's schemes...), they were able to develop these from refugee camps to fortified weapons facilities. Optimus tells us that "all we need is a little energon and a lot of luck," which suggests they were ready to begin an invasion of at least part of Cybertron when the movie began.
It's possible the moons also had an army of Cybertronian autobots who were destroyed, or that they were already on Cybertron waiting for the invasion. More autobots is always a good thing, but given Season 1 & 2 depicted Cybertron as baren, but the movie depicted it as having a robust Cybertronian population... in at least one city... it's not really clear what numbers we're working with, so all we really have to go by are Optimus and Megatron's plans, with Optimus planning full scale invasion, while Megatron plans to... destroy autobot city, thereby threatening the energon supply to the moons and/or undermining the Earth/Autobot alliance. This suggests, at least to me, that this isn't an issue of manpower, but of energon (which isn't surprising, since G1 Transformers was a rather unambiguous reaction to the 70s oil crisis) - if the autobots had a consistent supply of energon, they'd win the war. And guess what? It seems that they do regardless of whether Unicron shows up.
The second big difference is the leadership. Ultra Magnus seems to be battle hardened, but is more of a follower than a leader. He'd likely follow Optimus Prime's plans, but perhaps pause the invasion to rebuild Autobot City. Starscream, I suspect, won't fare much better; I suspect he'll want to shore up support for his leadership, which means two things: (1) small, symbolic victories he can brag about, and maybe (2) sending his rivals off to die. Neither of these are going to tip the war in the Decepticon's favor.
After a short period of relative calm, Ultra Magnus would be back in Optimus's position and follow through with his invasion of Cybertron. Starscream could follow in Megatron's footsteps and try to undercut this by sabotaging supply lines, or pre-emptively invading a moon, but I halfway suspect Starscream will sign a peace treaty at the first sign of a bloody nose, ceding half of Cybertron to the autobots, perhaps in exchange for energon aid. This could lead to a cold war on Earth, as Decepticons try to secure their own alliances, energon, or destabilize the human/autobot alliance.
The real threat, however, is Megatron who obviously still functions. If he gets picked up by the Quintessons or Junkions, he'd return to take over the Decepticons and likely catch Ultra Magnus unaware. It's also possible that disgruntled Decepticons might go looking for him, given the number of witnesses. No offense to Magnus, but Megatron is on a different level, and I suspect that if he's caught off guard, Ultra Magnus might fall, especially if Starscream's machinations really helped to put the Decepticons on a more solid footing.
