There are a few solutions to this problem that I would suggest. Please feel free to debate these GÇô I would be very interested to hear the thoughts of both shield and armour tankers.
1. Increase repair rate, especially at the basic level. I would suggest 4, 7, and 10 HP/s for the repair modules. This is a huge increase, but I think itGÇÖs needed to make repair modules effective. It also has the effect of making them have a noticeable effect for newbies.
2. Change the mobility penalty on the armour plates. ItGÇÖs very significant at the moment, especially for complex plates, which leads to complex plates being rarely used. A good idea would be to change the speed penalty to a stamina penalty, so it isnGÇÖt as harsh, but still impedes the mobility slightly. Also, reduce the penalty, so itGÇÖs something like 2%, 4%, and 6%. This would let complex plates actually be used. This isn't necessary if armour is buffed much - this would be a notable difference between shields and armour, the mobility vs HP tradeoff. It's important to maintain that difference and not make them too similar.
3. Increase the HP armour plates give to be in line with shields GÇô 65, 110, and 175. Again, this would make complex plates used. Not precise values, just to show the basic idea - the basic plate might need to be tweaked to keep the progression balanced. Kitten Empress suggested a good set of numbers here, which I have put in the 'Notable Feedback' section at the end of my post.
4. Change the bonuses on the armour suits to be something that actually fits an armour suit. The amarr suit has a good example of this - a repair bonus (though this is on the logistics suit, and it's the assault suits that needs these). An armour rep bonus would be good on a Gallente suit, for example, and a plate bonus for an Amarr suit.
5. Increase the base speed of armour tanking suits, improving the outcome when the plates are added. This encourages shield tanking on armour suits as well, though, so this on its own isn't sufficient. Credit to BL4CKST4R for the suggestion. This works best thematically with (overused example, but Gallente are the main armour tankers) Gallente, because of their short range gear, they need to get into range quicker.
6. Increase the delay before recharge on shields. This would emphasise the constant nature of armour repairers, and make it more significant, as well as helping to balance between the regeneration rates.