After playing around with it a while I want to add my thought about the hard-mode of agricraft:
I think the math which the config shows you is missleading. From what I see the chance for increasing/decreasing stats is actually "per stat". So with 4 parent'plants you have a 25% chance of decreasing on growth, gain or strength which then can actually happen quiet often.
So after raising a few plants to max I get the feeling of "one-third progress". So pretty much two third of the time you get a plant which you don't really want or can use for progressing towards getting a maxed plant.
The very positive side is, that you actually work with clippers (which usually are quiet unnecessary in agricraft else) and it actually makes fun and gives a real feeling of having achieved something when you finally see your seed showing the wanted "10/10/10".
It makes the work really feel more worth for the time you put in.
The negative side I sadly have to say is just the amount of seeds. Harvestcraft has over 50 seeds I think and if you actually focus on raising one seed after another (like I usually do *smirks*) it can become quiet am even more tedious work than normal-mode.
As a side-project (just having many seeds crossbreeding and looking at them only from time to time) I think it can work out as fun, slowly reaching your goal (so it fits quiet well into the pack).
The sheer amount of seeds you can/want to raise this way might scare people away from agricraft.
it feels like the hard mode is made for having around 20~30 seeds (so mainly the vanilla and agricraft seeds, including the special ones for botania/thaumcraft) but with the ~100 seeds (mostly cause of harvestcraft) you're really not allowed to focus on getting all seeds maxed first before planning to do other things.
To say it clearly: I'm
not saying the hard-mode is bad or anything, just want to share my opinion. I think it's actually quiet fun to have this challange. Just saying that you might have to do the breeding unfocused, as a side project, or you might get crazy
[edit]
I hope it was okay to post my opinion about mainly this agricraft specific mechanic. If it looks like the text might scare people away, tell me and I edit it out/delete it.
I think it's a great modpack and it's really fun to play. Teaches me alot about actually "calm down and slow down" again after playing so many modpacks which made me just hurry from one project to another
[edit #2]
And one advice for people new to playing with hardmode-agricraft (like me):
Use the clippers often. Every few crossbreeding pick a plant you want to as a new start and put everything else away. Then use clippers until you have 4 of these plant and start crossbreeding again.
Using the clippers alot helps tremendously to get your plants to max.