The intent is to provide players with a sense of pride and accomplishment for unlocking different heroes.
As for cost, we selected initial values based upon data from the Open Beta and other adjustments made to milestone rewards before launch. Among other things, we're looking at average per-player credit earn rates on a daily basis, and we'll be making constant adjustments to ensure that players have challenges that are compelling, rewarding, and of course attainable via gameplay.
We appreciate the candid feedback, and the passion the community has put forth around the current topics here on Reddit, our forums and across numerous social media outlets.
Our team will continue to make changes and monitor community feedback and update everyone as soon and as often as we can.

Hey all,
Apologies for not being more active these past weeks leading up to launch - as you know things get really hectic and you tend to spend whatever spare freetime you have recovering. I really regret not being here on the subreddit at the start of the early access. Hopefully some of these replies will bring some clarity and hope.
Performance during games will affect the amount of credits you get at the end of a match.
Matchmaking will take into account not only player skill, but also total gametime and rarity of star cards. This means that you will be matchmade with players with an average performance similar to you and (to the largest extent possible) not against players who are much better than you, whether by having higher rarity cards or by showing higher skill.
Heroes that are locked at launch will only be unlocked with credits, not crystals. The heroes, similar to the locked weapons for Troopers, are sidegrades instead of upgrades (Darth Vader should be on similar power level as Darth Maul, etc). The goal is to keep you playing for a long time and have something cool to look forward to as you earn credits.
Speaking of earning credits, we're constantly evaluating and tweaking the earn rates versus the cost of crates and heroes. The current rates were based on open beta data, but you should expect us to constantly evolve these numbers as we hit launch and onwards. There will also be more milestones that award credits and crafting parts available, as well as star cards only unlockable through those milestones. If all you want to do is play and grind towards your next unlock that will be fully possible and we'll continue to tweak the numbers until the requirements feel fun and achievable.
Working on a game with a live economy and without a premium content lineup is a new challenge for us at DICE. We had one progression system in the closed alpha and heard your feedback back then. We made another iteration for the open beta and heard your feedback then too. For launch, we're having another iteration and there will definitely be more iterations as we evolve this game post launch.
Your continous feedback as you play the game is absolutely invaluable and I encourage you to keep sending it our way. There is really no reason to "rebel" against us - we want this game to be as great and enjoyable as it can be - we're reading all your feedback and working as fast as we can to adjust the game to your liking.
The dev team will be around Battlefront II for a long time. I sincerely hope you'll be here with us!
Thanks,
Dennis