Suggested

Remove Boost from the game.

Maybe they worry about getting sued over used Formula One as a basis for the game play. Perhaps removing the boost completely would be best. 

Having this boost makes race lap records faster than qualifying which isn’t realistic for a one lap low fuel qualifying 

Because the stock reasoning behind said suggestions is to make this game mirror F1.  

If it's realism, I find the powerful DRS at higher levels to be more unrealistic than the Boost. I don't know why people don't talk about that more often. In the old iGP you didn't have Technology levels for KERS and Boost, which is the main reason why both are so much more powerful now, but I digress.

Boost in varying forms is currently being used in series like Indycar, DTM, and Super Formula. The boost system in this game is very similar to the current Indycar regs. Just like iGP, in Indycar on road courses, all cars have a set amount of boost or "push-to-pass" available, with no restrictions on when to use them or how much to use them at a time, in fact in Indycar you could use them even on restarts on road courses. So you can use them to attempt to overtake or defend, to pull a gap or to catch up to someone, to set a fast inlap, outlap, anything. In most racing series with boost there are racing drivers who'd obviously save quite a bit of boost for the final laps too. Similar to iGP.

Yes, in DTM they are only allowed to use boost a set number of times in the race. In F1 during the KERS era the cars had to charge the battery before being able to deploy boost (think it was around this time when iGP was first released). Now F1 has ERS which is more or less automatic. On a side note in certain series there's even limited DRS usage and different rules like not needing to be 1 sec behind to deploy DRS, some allow you to use DRS while in front even. But whatever boost system you prefer, on iGP the reason why the boost usage seems unrealistic is because of how boosting on this game usually guarantees an overtake (just like DRS on this game), a result of how the race simulation on iGP works, rather than the fault of boost alone. Unless you are Kimi Raikkonen in Spa 2009, in real life you don't often see racing drivers being able to pass tons of cars at once just by pushing a button.

Quite a number of racing series use boost, some like Indycar as I mentioned having a boost system similar to iGP, so yes, it is being used in real life. It's not because of boost alone that the racing seems arcade-y, but because of how the race simulation works as a whole.

And no, not all top managers on this game save everything for the last lap that often. Saving boost is good when you're able to, it gives you more options later in the race, but using boost aggressively or earlier in the race is also a viable tactic when done in the right circumstances. Things like the "shape" of the DRS train (due to the concertina effect, or "dirty air" effect), how strong DRS is on different tracks, and more contribute to how effective certain boost tactics are on this game. On some tracks it is better to conserve more, on others it may pay off to be more aggressive, or different managers may simply be able to pull off different tactics on different tracks against different opponents better.

Yes, I don't like pack racing (mostly due to DRS on this game), conserve-as-much-boost-as-possible racing either, but it's still racing even if it's somewhat arcade-y (like most racing games out there), and it's not like there's only one sure-fire boost tactic to win on iGP. Would I be up for some changes? Of course. Removing boost entirely? No, but personally I'm okay if both DRS and boost were nerfed (even though I'm fine with boost right now), but I don't think there's much demand for that. Either way, boost is at least a variable players can control.

Agree with most above, but even in Indycar push time is restricted to 15-20 sec max

How many seconds do they gain on laptime over that 15-20 seconds, do you know..... 

Yeah, I kind of agree but I think we need more input in a race other than just PL. I'd like to see an end to boost but replaced with something else, I'm just not sure what

How about it's replaced by team orders when the manager can radio a driver to tell them to let there teammate through or not challenge the lead driver... the driver could then respond with a positive, negative or neutral response.. this could affect the driver's morale post race and their willingness to sign a new contract or leave the team for another.

+1
I agree that disabling the boost would make the championship more realistic.

Why not have ten shots of ten seconds of boost available to every driver at the start of every race? 

I really like this idea but as an additional feature, rather than a replacement for boost

I would suggest that even if the manager is logged in, there should be an option that puts the drivers in charge of the boost, because its very overwhelming for new people joining the game, to take care of the strategy and also the boost. Make an option to have either manual control of the boost or transfer full control to the driver.